View Filing Data

Print Document View Excel Document

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2018	Nov. 02, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Trading Symbol	BWXT
Entity Registrant Name	BWX Technologies, Inc.
Entity Central Index Key	0001486957
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)		98,726,135

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 66,125	$ 203,404
Restricted cash and cash equivalents	4,359	7,105
Investments	2,732	2,934
Accounts receivable – trade, net	194,575	189,217
Accounts receivable – other	46,183	19,365
Contracts in progress	326,355	420,628
Other current assets	44,528	30,437
Total Current Assets	684,857	873,090
Property, Plant and Equipment	1,073,893	1,013,141
Less accumulated depreciation	684,530	664,512
Net Property, Plant and Equipment	389,363	348,629
Investments	8,604	9,301
Goodwill	278,939	218,331
Deferred Income Taxes	45,105	86,740
Investments in Unconsolidated Affiliates	62,160	43,266
Intangible Assets	240,081	110,405
Other Assets	26,595	22,577
TOTAL	1,735,704	1,712,339
Current Liabilities:
Current maturities of long-term debt	14,745	27,870
Accounts payable	100,004	93,421
Accrued employee benefits	74,398	82,477
Accrued liabilities – other	53,508	64,738
Advance billings on contracts	104,646	246,192
Accrued warranty expense	12,426	13,428
Total Current Liabilities	359,727	528,126
Long-Term Debt	756,492	481,059
Accumulated Postretirement Benefit Obligation	20,111	21,368
Environmental Liabilities	89,429	79,786
Pension Liability	102,093	296,444
Other Liabilities	15,351	19,799
Commitments and Contingencies (Note 5)
Stockholders' Equity:
Common stock, par value $0.01 per share, authorized 325,000,000 shares; issued 125,796,671 and 125,381,591 shares at September 30, 2018 and December 31, 2017, respectively	1,258	1,254
Preferred stock, par value $0.01 per share, authorized 75,000,000 shares; No shares issued	0	0
Capital in excess of par value	112,300	98,843
Retained earnings	1,159,552	990,652
Treasury stock at cost, 27,070,536 and 25,964,088 shares at September 30, 2018 and December 31, 2017, respectively	(884,200)	(814,809)
Accumulated other comprehensive income	3,542	9,454
Stockholders' Equity – BWX Technologies, Inc.	392,452	285,394
Noncontrolling interest	49	363
Total Stockholders' Equity	392,501	285,757
TOTAL	$ 1,735,704	$ 1,712,339

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	325,000,000	325,000,000
Common stock, shares issued (in shares)	125,796,671	125,381,591
Preferred stock, par value (in usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	75,000,000	75,000,000
Preferred stock, shares issued (in shares)	0	0
Treasury stock at cost, shares (in shares)	27,070,536	25,964,088

Condensed Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenues	$ 425,507	$ 419,360	$ 1,321,891	$ 1,257,600
Costs and Expenses:
Cost of operations	326,314	302,267	971,887	883,839
Research and development costs	3,959	2,597	11,673	5,268
Losses (gains) on asset disposals and impairments, net	243	(2)	(2)	(33)
Selling, general and administrative expenses	53,919	51,351	159,199	150,881
Total Costs and Expenses	384,435	356,213	1,142,757	1,039,955
Equity in Income of Investees	9,323	3,630	22,698	10,832
Operating Income	50,395	66,777	201,832	228,477
Other Income (Expense):
Interest income	1,121	402	2,340	750
Interest expense	(7,925)	(3,837)	(19,354)	(11,260)
Other – net	40,968	7,252	63,984	21,487
Total Other Income (Expense)	34,164	3,817	46,970	10,977
Income before Provision for Income Taxes	84,559	70,594	248,802	239,454
Provision for Income Taxes	6,482	23,901	43,578	75,556
Net Income	78,077	46,693	205,224	163,898
Net Income Attributable to Noncontrolling Interest	(158)	(140)	(201)	(364)
Net Income Attributable to BWX Technologies, Inc.	$ 77,919	$ 46,553	$ 205,023	$ 163,534
Basic:
Net Income Attributable to BWX Technologies, Inc. (in usd per share)	$ 0.78	$ 0.47	$ 2.06	$ 1.65
Diluted:
Net Income Attributable to BWX Technologies, Inc. (in usd per share)	$ 0.78	$ 0.46	$ 2.04	$ 1.63
Shares used in the computation of earnings per share (Note 10):
Basic (in shares)	99,421,031	99,328,677	99,542,933	99,313,264
Diluted (in shares)	100,420,766	100,260,255	100,501,597	100,367,383

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net Income	$ 78,077	$ 46,693	$ 205,224	$ 163,898
Other Comprehensive Income (Loss):
Currency translation adjustments	2,008	4,590	(4,725)	7,425
Derivative financial instruments:
Unrealized (losses) gains arising during the period, net of tax benefit (provision) of $24, $90, $(5) and $(149), respectively	(39)	(259)	7	429
Reclassification adjustment for (gains) losses included in net income, net of tax provision (benefit) of $7, $(71), $16 and $0, respectively	(26)	204	(41)	(3)
Amortization of benefit plan costs, net of tax benefit of $(78), $(146), $(286) and $(459), respectively	360	282	1,145	861
Investments:
Unrealized losses arising during the period, net of tax benefit (provision) of $270, $(52), $270 and $(182), respectively	(388)	(227)	(432)	(1,531)
Reclassification adjustment for losses (gains) included in net income, net of tax provision of $25, $5, $25 and $19, respectively	379	(9)	379	(143)
Other Comprehensive Income (Loss)	2,294	4,581	(3,667)	7,038
Total Comprehensive Income	80,371	51,274	201,557	170,936
Comprehensive Income Attributable to Noncontrolling Interest	(158)	(140)	(201)	(364)
Comprehensive Income Attributable to BWX Technologies, Inc.	$ 80,213	$ 51,134	$ 201,356	$ 170,572

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Tax provision of unrealized gains on derivative financial instruments	$ 24	$ 90	$ (5)	$ (149)
Tax provision (benefit) on reclassification adjustment for (gains) losses on derivative financial instruments	7	(71)	16	0
Tax benefit of amortization of benefit plan costs	(78)	(146)	(286)	(459)
Tax (provision) benefit of unrealized gains (losses)	270	(52)	270	(182)
Tax provision on reclassification adjustment for gain on investment	$ 25	$ 5	$ 25	$ 19

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Capital In Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Stockholders' Equity	Noncontrolling Interest
Beginning balance (in shares) at Dec. 31, 2016		124,149,609
Beginning balance at Dec. 31, 2016	$ 150,410	$ 1,241	$ 22,018	$ 885,117	$ 3,811	$ (762,169)	$ 150,018	$ 392
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	163,898			163,534			163,534	364
Dividends declared	(31,107)			(31,107)			(31,107)
Currency translation adjustments	7,425				7,425		7,425
Derivative financial instruments	426				426		426
Defined benefit obligations	861				861		861
Available-for-sale investments	(1,674)				(1,674)		(1,674)
Exercise of stock options (in shares)		874,872
Exercise of stock options	20,611	$ 9	20,602				20,611
Shares placed in treasury	(12,073)		39,907			(51,980)	(12,073)
Stock-based compensation charges (in shares)		286,187
Stock-based compensation charges	9,879	$ 3	9,876				9,879
Distributions to noncontrolling interests	(415)							(415)
Ending balance (in shares) at Sep. 30, 2017		125,310,668
Ending balance at Sep. 30, 2017	$ 308,241	$ 1,253	92,403	1,017,544	10,849	(814,149)	307,900	341
Beginning balance (in shares) at Dec. 31, 2017	125,381,591	125,381,591
Beginning balance at Dec. 31, 2017	$ 285,757	$ 1,254	98,843	990,652	9,454	(814,809)	285,394	363
Recently adopted accounting standards at Dec. 31, 2017	9,926			12,171	(2,245)		9,926
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	205,224			205,023			205,023	201
Dividends declared	(48,294)			(48,294)			(48,294)
Currency translation adjustments	(4,725)				(4,725)		(4,725)
Derivative financial instruments	(34)				(34)		(34)
Defined benefit obligations	1,145				1,145		1,145
Available-for-sale investments	(53)				(53)		(53)
Exercise of stock options (in shares)		207,686
Exercise of stock options	4,942	$ 2	4,940				4,942
Shares placed in treasury	(69,391)					(69,391)	(69,391)
Stock-based compensation charges (in shares)		207,394
Stock-based compensation charges	8,519	$ 2	8,517				8,519
Distributions to noncontrolling interests	$ (515)							(515)
Ending balance (in shares) at Sep. 30, 2018	125,796,671	125,796,671
Ending balance at Sep. 30, 2018	$ 392,501	$ 1,258	$ 112,300	$ 1,159,552	$ 3,542	$ (884,200)	$ 392,452	$ 49

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Statement of Stockholders' Equity [Abstract]
Dividends declared per share (in usd per share)	$ 0.48	$ 0.31

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	$ 205,224	$ 163,898
Non-cash items included in net income from continuing operations:
Depreciation and amortization	43,692	42,135
Income of investees, net of dividends	(8,471)	731
Gains on asset disposals and impairments, net	(2)	(33)
Gain on forward contracts	(4,743)	0
Recognition of debt issuance costs from Former Credit Facility	2,441	0
Provision for deferred taxes	38,685	17,501
Recognition of (gains) losses for pension and postretirement plans	(33,699)	1,320
Stock-based compensation expense	8,519	9,879
Changes in assets and liabilities:
Accounts receivable	3,384	(17,748)
Accounts payable	2,061	(10,978)
Contracts in progress and advance billings on contracts	(35,049)	(2,963)
Income taxes	(46,511)	21,587
Accrued and other current liabilities	3,344	(33,736)
Pension liability, accrued postretirement benefit obligation and employee benefits	(184,898)	(47,109)
Other, net	(2,418)	345
NET CASH (USED IN) PROVIDED BY OPERATING ACTIVITIES	(8,441)	144,829
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property, plant and equipment	(60,488)	(49,361)
Acquisition of business	(212,993)	0
Purchases of securities	(3,111)	(3,237)
Sales and maturities of securities	3,378	12,406
Investments, net of return of capital, in equity method investees - payments	(9,037)
Investments, net of return of capital, in equity method investees - proceeds		2,142
Proceeds from asset disposals	499	142
Other, net	4,743	(24)
NET CASH USED IN INVESTING ACTIVITIES	(277,009)	(37,932)
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings of long-term debt	901,300	73,600
Repayments of long-term debt	(624,987)	(94,320)
Payment of debt issuance costs	(9,443)	0
Repurchase of common shares	(62,558)	0
Dividends paid to common shareholders	(48,014)	(31,072)
Exercise of stock options	3,511	16,019
Cash paid for shares withheld to satisfy employee taxes	(5,402)	(7,389)
Other	(515)	(415)
NET CASH PROVIDED BY (USED IN) FINANCING ACTIVITIES	153,892	(43,577)
EFFECTS OF EXCHANGE RATE CHANGES ON CASH	(8,464)	15,290
TOTAL (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS AND RESTRICTED CASH AND CASH EQUIVALENTS	(140,022)	78,610
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	213,144	134,600
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH AND CASH EQUIVALENTS AT END OF PERIOD	73,122	213,210
Cash paid during the period for:
Interest	13,325	10,762
Income taxes (net of refunds)	51,779	36,425
SCHEDULE OF NON-CASH INVESTING ACTIVITY:
Accrued capital expenditures included in accounts payable	$ 13,457	$ 7,680

Basis of Presentation and Significant Accounting Policies

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Basis of Presentation and Significant Accounting Policies

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES

We have presented the condensed consolidated financial statements of BWX Technologies, Inc. ("BWXT" or the "Company") in U.S. dollars in accordance with the interim reporting requirements of Form 10-Q, Rule 10-01 of Regulation S-X and accounting principles generally accepted in the United States ("GAAP"). Certain financial information and disclosures normally included in our financial statements prepared annually in accordance with GAAP have been condensed or omitted. Readers of these financial statements should, therefore, refer to the consolidated financial statements and notes in our annual report on Form 10-K for the year ended December 31, 2017 (our "2017 10-K"). We have included all adjustments, in the opinion of management, consisting only of normal recurring adjustments, necessary for a fair presentation.

We use the equity method to account for investments in entities that we do not control, but over which we have the ability to exercise significant influence. We generally refer to these entities as "joint ventures." We have eliminated all intercompany transactions and accounts. We have reclassified certain amounts previously reported to conform to the presentation at September 30, 2018 and for the three and nine months ended September 30, 2018. We present the notes to our condensed consolidated financial statements on the basis of continuing operations, unless otherwise stated.

Unless the context otherwise indicates, "we," "us" and "our" mean BWXT and its consolidated subsidiaries.

Reportable Segments

We operate in three reportable segments: Nuclear Operations Group, Nuclear Services Group and Nuclear Power Group. Our reportable segments are further described as follows:

•

Our Nuclear Operations Group segment manufactures naval nuclear reactors for the Naval Nuclear Propulsion Program for use in U.S. Navy submarines and aircraft carriers. Through this segment, we own and operate manufacturing facilities located in Lynchburg, Virginia; Barberton, Ohio; Mount Vernon, Indiana; Euclid, Ohio; and Erwin, Tennessee. The Lynchburg operations fabricate fuel-bearing precision components that range in weight from a few grams to hundreds of tons. In-house capabilities also include wet chemistry uranium processing, advanced heat treatment to optimize component material properties and a controlled, clean-room environment with the capacity to assemble railcar-size components. The Barberton and Mount Vernon locations specialize in the design and manufacture of heavy components inclusive of development and fabrication activities for submarine missile launch tubes at the Mount Vernon facility. The Euclid facility fabricates electro-mechanical equipment and performs design, manufacturing, inspection, assembly and testing activities. Fuel for the naval nuclear reactors is provided by Nuclear Fuel Services, Inc. ("NFS"), one of our wholly owned subsidiaries. Located in Erwin, NFS also downblends Cold War-era government stockpiles of high-enriched uranium into material suitable for further processing into commercial nuclear reactor fuel.

•

Our Nuclear Services Group segment provides various services to the U.S. Government and the commercial nuclear industry. Services provided to the U.S. Government include nuclear materials management and operation, environmental management and administrative and operating services for various U.S. Government-owned facilities. These services are provided to the U.S. Department of Energy ("DOE"), including the National Nuclear Security Administration ("NNSA"), the Office of Nuclear Energy, the Office of Science and the Office of Environmental Management, and NASA. Through this segment we deliver services and management solutions to nuclear and high-consequence operations. A significant portion of this segment's operations are conducted through joint ventures.

Our Nuclear Services Group segment also provides inspection and maintenance services primarily for the U.S. commercial nuclear industry including steam generator and heat exchanger inspection services, high pressure water lancing, non-destructive examination and customized tooling solutions. This segment also offers complete advanced fuel and reactor engineering, licensing and manufacturing services for new advanced nuclear reactors.

•

Our Nuclear Power Group segment fabricates steam generators, nuclear fuel, fuel handling systems, pressure vessels, reactor components, heat exchangers, tooling delivery systems and other auxiliary equipment, including containers for the storage of spent nuclear fuel and other high-level waste, for nuclear utility customers. BWXT has supplied the nuclear industry with more than 1,300 large, heavy components worldwide and is the only heavy nuclear component, N-Stamp certified manufacturer in North America. This segment also provides specialized engineering services that include structural component design, 3-D thermal-hydraulic engineering analysis, weld and robotic process development, electrical and controls engineering and metallurgy and materials engineering. In addition, this segment offers in-plant inspection, maintenance and modification services for nuclear steam generators, heat exchangers, reactors, fuel handling systems and balance of plant equipment, as well as specialized non-destructive examination and tooling/repair solutions.

On July 30, 2018, our subsidiary BWXT ITG Canada, Inc. acquired Sotera Health's Nordion medical isotope business (the "MI business") for $213.0 million, subject to customary working capital, cash and debt adjustments. The MI business is a leading global manufacturer and supplier of critical medical isotopes and radiopharmaceuticals for research, diagnostic and therapeutic uses. Its customers include radiopharmaceutical companies, hospitals and radiopharmacies. Its primary operations are located in Kanata, Ontario and Vancouver, British Columbia. This acquisition adds approximately 150 highly trained and experienced personnel, two specialized production centers and a uniquely licensed infrastructure. In addition to the growing portfolio of radioisotope products we acquired, the MI business will be the platform from which we plan to launch our Molybdenum-99 product line and a number of future radioisotope-based imaging and therapeutic products. This business is reported as part of our Nuclear Power Group segment. See Note 2 for additional information on the acquisition of the MI business.

See Note 9 for financial information about our segments. Operating results for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018. For further information, refer to the consolidated financial statements and the related footnotes included in our 2017 10-K.

Deconsolidation of Generation mPower LLC

On March 2, 2016, we entered into a framework agreement with Bechtel Power Corporation ("Bechtel"), BWXT Modular Reactors, LLC and BDC NexGen Power, LLC for the potential restructuring and restart of our mPower small modular reactor program (the "Framework Agreement"). As a result of entering into the Framework Agreement, we deconsolidated Generation mPower LLC ("GmP") from our financial statements as of the date of the Framework Agreement and recognized a $30.0 million loss contingency, which was ultimately paid to Bechtel in the first quarter of 2017 following the receipt of Bechtel's notice that the mPower program would not be restarted.

Contracts and Revenue Recognition

We generally recognize contract revenues and related costs over time for individual performance obligations based on a cost-to-cost method in accordance with Financial Accounting Standards Board ("FASB") Topic Revenue from Contracts with Customers. We recognize estimated contract revenue and resulting income based on the measurement of the extent of progress toward completion as a percentage of the total project (percentage-of-completion basis). Certain costs may be excluded from the cost-to-cost method of measuring progress, such as significant costs for uninstalled materials, if such costs do not depict our performance in transferring control of goods or services to the customer. We review contract price and cost estimates periodically as the work progresses and reflect adjustments proportionate to the percentage-of-completion in income in the period when those estimates are revised. Certain of our contracts recognize revenue at a point in time, and revenue on these contracts is recognized when control transfers to the customer. The majority of our revenue that is recognized at a point in time is related to parts and certain medical isotopes and radiopharmaceuticals in our Nuclear Power Group segment. For all contracts, if a current estimate of total contract cost indicates a loss on a contract, the projected loss is recognized in full when determined.

Accumulated Other Comprehensive Income

The components of Accumulated other comprehensive income included in Stockholders' Equity are as follows:



	September 30, 2018			December 31, 2017
	(In thousands)
Currency translation adjustments	$	8,423		$	13,148
Net unrealized gain on derivative financial instruments	319			353
Unrecognized prior service cost on benefit obligations	(5,092		)	(6,237		)
Net unrealized gain (loss) on available-for-sale investments	(108		)	2,190
Accumulated other comprehensive income	$	3,542		$	9,454

Upon adopting the FASB update to the Topic Financial Instruments, we reclassified $2.2 million of net unrealized gains on available-for-sale investments from Accumulated other comprehensive income to Retained earnings on January 1, 2018.

The amounts reclassified out of Accumulated other comprehensive income by component and the affected condensed consolidated statements of income line items are as follows:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
Accumulated Other Comprehensive Income (Loss) Component Recognized	(In thousands)												Line Item Presented
Realized gain (loss) on derivative financial instruments	$	(86	)	$	195		$	(90	)	$	182		Revenues
	119			(470		)	147			(179		)	Cost of operations
	33			(275		)	57			3			Total before tax
	(7		)	71			(16		)	—			Provision for Income Taxes
	$	26		$	(204	)	$	41		$	3		Net Income
Amortization of prior service cost on benefit obligations	$	(438	)	$	(428	)	$	(1,431	)	$	(1,320	)	Other – net
	78			146			286			459			Provision for Income Taxes
	$	(360	)	$	(282	)	$	(1,145	)	$	(861	)	Net Income
Realized gain (loss) on investments	$	(354	)	$	14		$	(354	)	$	162		Other – net
	(25		)	(5		)	(25		)	(19		)	Provision for Income Taxes
	$	(379	)	$	9		$	(379	)	$	143		Net Income
Total reclassification for the period	$	(713	)	$	(477	)	$	(1,483	)	$	(715	)

Inventories

At September 30, 2018 and December 31, 2017, Other current assets included inventories totaling $15.5 million and $8.6 million, respectively, consisting entirely of raw materials and supplies.

Restricted Cash and Cash Equivalents

At September 30, 2018, we had restricted cash and cash equivalents totaling $7.0 million, $2.6 million of which was held for future decommissioning of facilities (which is included in Other Assets on our condensed consolidated balance sheets) and $4.4 million of which was held to meet reinsurance reserve requirements of our captive insurer.

The following table provides a reconciliation of cash and cash equivalents and restricted cash and cash equivalents within our condensed consolidated balance sheets to the totals presented in our condensed consolidated statement of cash flows:



	September 30, 2018		December 31, 2017
	(In thousands)
Cash and cash equivalents	$	66,125	$	203,404
Restricted cash and cash equivalents	4,359		7,105
Restricted cash and cash equivalents included in Other Assets	2,638		2,635
Total cash and cash equivalents and restricted cash and cash equivalents as presented in our condensed consolidated statement of cash flows	$	73,122	$	213,144

Warranty Expense

We accrue estimated warranty expense, included in Cost of operations on our condensed consolidated statements of income, to satisfy contractual warranty requirements when we recognize the associated revenue on the related contracts. In addition, we record specific provisions or reductions where we expect the actual warranty costs to significantly differ from the accrued estimates. Such changes could have a material effect on our consolidated financial condition, results of operations and cash flows.

The following summarizes the changes in the carrying amount of our Accrued warranty expense:



	Nine Months Ended September 30,
	2018			2017
	(In thousands)
Balance at beginning of period	$	13,428		$	11,477
Additions	1,136			1,011
Expirations and other changes	(1,400		)	(188		)
Payments	(482		)	(21		)
Translation	(256		)	434
Balance at end of period	$	12,426		$	12,713

Provision for Income Taxes

We are subject to federal income tax in the U.S. and Canada as well as income tax within multiple U.S. state jurisdictions. We provide for income taxes based on the enacted tax laws and rates in the jurisdictions in which we conduct our operations. These jurisdictions may have regimes of taxation that vary with respect to nominal rates and with respect to the basis on which these rates are applied. This variation, along with changes in our mix of income within these jurisdictions, can contribute to shifts in our effective tax rate from period to period.

On December 22, 2017, the Tax Cuts and Jobs Act (the "Act") was enacted, making significant changes to existing U.S. tax laws that impact us, including, but not limited to, a reduction to the U.S. corporate income tax rate from 35% to 21% for tax years beginning after December 31, 2017, the taxation of global intangible low-taxed income ("GILTI") and additional deduction limitations related to executive compensation. We recognized the income tax effects of the Act within our condensed consolidated financial statements in accordance with FASB Topic Income Taxes. Our Canadian operations continue to be subject to tax at a local statutory rate of approximately 25%.

Our effective tax rate for the three months ended September 30, 2018 was 7.7% as compared to 33.9% for the three months ended September 30, 2017. Our effective tax rate for the nine months ended September 30, 2018 was 17.5% as compared to 31.6% for the nine months ended September 30, 2017. The effective tax rates for the three and nine months ended September 30, 2018 were lower than the 2018 U.S. corporate income tax rate of 21% primarily due to remeasurement adjustments to our deferred tax assets as a result of accelerating additional contributions made in August 2018 to certain of our domestic pension plans for inclusion in our 2017 U.S. tax return. Our effective tax rate for the nine months ended September 30, 2017 was lower than the 2017 U.S. corporate income tax rate of 35% primarily due to benefits recognized for excess tax benefits related to employee share-based payments of $5.4 million.

As of September 30, 2018, we had gross unrecognized tax benefits of $0.3 million (exclusive of interest and federal and state benefits), all of which would reduce our effective tax rate if recognized.

Recently Adopted Accounting Standards

There were no accounting standards adopted during the period covered by this Form 10-Q. For more information regarding recently adopted accounting standards, refer to Note 1 to the consolidated financial statements in Part II of our 2017 10-K, as updated by our Form 10-Q for the quarter ended March 31, 2018.

New Accounting Standards

In February 2016, the FASB issued an update to the Topic Leases, which supersedes the lease reporting requirements in Topic Leases (previously "FAS 13"). This update requires that a lessee recognize on its balance sheet the assets and liabilities for all leases with lease terms of more than 12 months, along with additional qualitative and quantitative disclosures. The effect of leases in a consolidated statement of income and a consolidated statement of cash flows is expected to be largely unchanged. Accounting by lessors was not significantly impacted by this update. This update will be effective for us in 2019, with early adoption permitted. We expect to adopt the provisions in this update effective January 1, 2019 using the modified retrospective approach. We do not anticipate a material impact on our financial statements upon adoption.

Acquisitions

9 Months Ended

Sep. 30, 2018

Business Combinations [Abstract]

Acquisitions

ACQUISITIONS

Acquisition of Sotera Health LLC's Nordion Medical Isotope Business

The purchase price of the acquisition has been allocated among assets acquired and liabilities assumed at fair value, with the excess purchase price recorded as goodwill. Our preliminary purchase price allocation, as follows, is subject to change upon receipt of additional information and completion of further analysis, including, but not limited to, finalization of valuations related to long-lived and intangible assets (amounts in thousands):



Accounts receivable – trade	$	7,732
Contracts in progress	51
Inventories	2,113
Other current assets	97
Property, plant and equipment	12,948
Goodwill	62,495
Deferred Income Taxes	3,006
Intangible assets	139,257
Total assets acquired	$	227,699
Accounts payable	$	654
Accrued employee benefits	579
Accrued liabilities – other	1,665
Environmental liabilities	2,062
Pension liability	9,746
Total liabilities assumed	$	14,706
Net assets acquired	$	212,993
Amount of tax deductible goodwill	$	53,693

The intangible assets included above consist of the following (dollar amounts in thousands):



	Amount		Amortization Period
Technical support agreement and relationship	$	67,500	23 years
Unpatented technology	$	33,000	19 years
Favorable operating leases	$	28,157	13-30 years
Customer relationship	$	10,600	19 years

Our consolidated financial statements for the three and nine months ended September 30, 2018 include $8.0 million of revenues and $0.5 million of net income related to the MI business operations occurring from the acquisition date to September 30, 2018. Additionally, the following unaudited pro forma financial information presents our results of operations for the three and nine months ended September 30, 2018 and 2017 as if the acquisition of the MI business had occurred on January 1, 2017. The unaudited pro forma financial information below is not intended to represent or be indicative of our actual consolidated results had we completed the acquisition at January 1, 2017. This information is presented for comparative purposes only and should not be taken as representative of our future consolidated results of operations.



	Three Months Ended				Nine Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
	(In thousands, except per share amounts)
Revenues	$	429,558	$	429,791	$	1,347,031	$	1,285,536
Net Income Attributable to BWX Technologies, Inc.	$	79,141	$	45,788	$	206,435	$	159,499
Basic Earnings per Common Share	$	0.80	$	0.46	$	2.07	$	1.61
Diluted Earnings per Common Share	$	0.79	$	0.46	$	2.05	$	1.59

The unaudited pro forma results include the following pre-tax adjustments to the historical results presented above:


•	Increase in amortization expense related to timing of amortization of the fair value of identifiable intangible assets acquired of approximately $0.5 million and $3.7 million for the three and nine months ended September 30, 2018, respectively, and $1.6 million and $4.8 million for the three and nine months ended September 30, 2017, respectively.


•	Additional interest expense associated with the incremental borrowings that would have been incurred to acquire the MI business as of January 1, 2017 of approximately $2.4 million for the nine months ended September 30, 2018, and $1.4 million and $3.8 million for the three and nine months ended September 30, 2017, respectively.


•	Elimination of $0.9 million and $2.5 million in acquisition related costs recognized in the three and nine months ended September 30, 2018, respectively, that are not expected to be recurring.

Revenue Recognition

9 Months Ended

Sep. 30, 2018

Revenue from Contract with Customer [Abstract]

Revenue Recognition

REVENUE RECOGNITION

The initial impact of the adoption of the FASB Topic Revenue from Contracts with Customers, which was recognized in a cumulative catch-up adjustment on January 1, 2018, is illustrated below:



	January 1,		December 31,
	2018		2017
	(In thousands)
Assets:
Contracts in progress	$	260,932	$	420,628
Deferred Income Taxes	$	85,193	$	86,740
Liabilities:
Accrued liabilities – other	$	66,371	$	64,738
Advance billings on contracts	$	73,390	$	246,192
Stockholders' Equity:
Retained earnings	$	1,000,578	$	990,652

Within our Nuclear Operations Group segment, we continue to recognize revenue over time and now measure progress on performance obligations using a cost-to-cost method. Historically, we utilized man-hours or a cost-to-cost method to measure progress on certain performance obligations within this segment. The performance obligations identified for recognizing revenue are similar to our historical units of account. As a result of the change to a cost-to-cost method, the timing of revenue recognition on affected contracts, in the aggregate, results in the recognition of revenue and cost of operations earlier in the process of satisfying performance obligations. This change impacted the life-to-date revenue and cost of operations recognized on performance obligations, and the adjustment to capture the impact of the new revenue recognition standard was recorded as a cumulative catch-up adjustment in Retained earnings. The new standard also resulted in a reduction in both our Contracts in progress and Advance billings on contracts account balances as a result of measuring the asset and liability at the contract level. Historically, contract assets and liabilities were measured at the unit of account, which we concluded was at a lower level than that of the contract.

The impact of the adoption of the new revenue standard on our Nuclear Power Group and Nuclear Services Group segments was not material.

Contracts and Revenue Recognition

Nuclear Operations Group

Our Nuclear Operations Group segment recognizes revenue over time for the manufacturing of naval nuclear reactor components and fuel, submarine missile launch tubes and the downblending of high-enriched uranium. Certain of our contracts contain two or more different types of components, each of which we identify as a separate performance obligation. We recognize revenue using a cost-to-cost method to measure progress as control is continually transferred to the customer as we incur costs on the performance obligations. We allocate revenue to the individual performance obligations within contracts with multiple performance obligations based on the stand-alone selling price of the individual performance obligations.

Our fixed-price incentive fee contracts include incentives that we concluded to be variable consideration. The amount of the variable consideration to which we are entitled is dependent on our actual costs incurred on the performance obligation compared to the target costs for that performance obligation and subject to incentive price revisions included within the contracts. We include these incentive fees in revenue when there is sufficient evidence to determine that the variable consideration is not constrained. The remaining contracts typically have immaterial amounts of variable consideration and have a single performance obligation. Our estimates of variable consideration and total estimated costs at completion are determined through a detailed process based on historical performance and our expertise using the most likely method. Variations from estimated contract performance could result in a material effect on our financial condition and results of operations in future periods.

Our Nuclear Operations Group segment's contracts allow for billings as costs are incurred, subject to certain retainages on our fixed-price incentive fee contracts, that require milestones to be reached for the remaining consideration to be paid.

Nuclear Services Group

Our contracts within our Nuclear Services Group segment are primarily cost-plus service contracts on which we recognize revenue over time based on a cost-to-cost method, which is consistent with the structure of the billings associated with these contracts. Ownership continuously transfers to the customer as we perform the services. The contracts within this segment do not contain significant variable consideration and contain a single performance obligation. Certain of these contracts contain assurance warranties and/or provisions for liquidated damages, which are expected to have an immaterial impact on the contracts based on our historical experience.

Nuclear Power Group

Our Nuclear Power Group segment recognizes revenue over time using a cost-to-cost method for the manufacturing of large components, non-standard parts, fuel bundles and service contracts as control continually transfers to the customers. For standard parts, revenue is recognized at the point in time control transfers to the customer, which is consistent with the transfer of ownership. For medical isotopes, we recognize revenue either at the point in time control transfers to the customer or over time using a unit of output method. This segment generates revenue primarily from firm-fixed-price contracts that do not contain variable consideration as well as time-and-materials based contracts. Certain of these contracts contain assurance warranties and/or provisions for liquidated damages, which are expected to have an immaterial impact to the contracts based on our historical experience. We are entitled to payment on the majority of our Nuclear Power Group segment contracts when we achieve certain milestones related to our progress.

Disaggregated Revenues

Revenues by geographical area and customer type are as follows:



	Three Months Ended September 30, 2018									Nine Months Ended September 30, 2018
	Nuclear Operations Group		Nuclear Services Group		Nuclear Power Group		Total			Nuclear Operations Group		Nuclear Services Group		Nuclear Power Group		Total
	(In thousands)
United States:
Government	$	315,744	$	27,120	$	—	$	342,864		$	960,271	$	81,175	$	—	$	1,041,446
Non-Government	2,066		536		3,890		6,492			5,915		7,623		4,477		18,015
	$	317,810	$	27,656	$	3,890	$	349,356		$	966,186	$	88,798	$	4,477	$	1,059,461
Canada:
Government	$	358	$	—	$	—	$	358		$	358	$	—	$	—	$	358
Non-Government	161		611		65,234		66,006			161		2,096		212,302		214,559
	$	519	$	611	$	65,234	$	66,364		$	519	$	2,096	$	212,302	$	214,917
Other:
Government	$	—	$	—	$	—	$	—		$	—	$	—	$	—	$	—
Non-Government	996		99		10,038		11,133			1,391		101		50,896		52,388
	$	996	$	99	$	10,038	$	11,133		$	1,391	$	101	$	50,896	$	52,388
Segment Revenues	$	319,325	$	28,366	$	79,162	426,853			$	968,096	$	90,995	$	267,675	1,326,766
Adjustments and Eliminations							(1,346		)							(4,875		)
Revenues							$	425,507								$	1,321,891

Revenues by timing of transfer of goods or services are as follows:



	Three Months Ended September 30, 2018									Nine Months Ended September 30, 2018
	Nuclear Operations Group		Nuclear Services Group		Nuclear Power Group		Total			Nuclear Operations Group		Nuclear Services Group		Nuclear Power Group		Total
	(In thousands)
Over-time	$	319,325	$	28,366	$	66,219	$	413,910		$	968,096	$	90,995	$	240,652	$	1,299,743
Point-in-time	—		—		12,943		12,943			—		—		27,023		27,023
Segment Revenues	$	319,325	$	28,366	$	79,162	426,853			$	968,096	$	90,995	$	267,675	1,326,766
Adjustments and Eliminations							(1,346		)							(4,875		)
Revenues							$	425,507								$	1,321,891

Revenues by contract type are as follows:



	Three Months Ended September 30, 2018									Nine Months Ended September 30, 2018
	Nuclear Operations Group		Nuclear Services Group		Nuclear Power Group		Total			Nuclear Operations Group		Nuclear Services Group		Nuclear Power Group		Total
	(In thousands)
Fixed-Price Incentive Fee	$	255,944	$	—	$	3,748	$	259,692		$	763,334	$	—	$	13,365	$	776,699
Firm-Fixed-Price	38,262		4,393		58,451		101,106			137,792		15,435		177,035		330,262
Cost-Plus Fee	25,117		23,496		—		48,613			66,800		73,535		45		140,380
Time-and-Materials	2		477		16,963		17,442			170		2,025		77,230		79,425
Segment Revenues	$	319,325	$	28,366	$	79,162	426,853			$	968,096	$	90,995	$	267,675	1,326,766
Adjustments and Eliminations							(1,346		)							(4,875		)
Revenues							$	425,507								$	1,321,891

Performance Obligations

As we progress on our contracts and the underlying performance obligations for which we recognize revenue over time, we refine our estimates of variable consideration and total estimated costs at completion, which impact the overall profitability on our contracts and performance obligations. Changes in these estimates result in the recognition of cumulative catch-up adjustments that impact our revenue and/or costs of contracts. During the nine months ended September 30, 2018, we recognized net favorable changes in estimates that resulted in increases in revenue of $23.4 million and an increase in cost of operations of $12.3 million. Included in these amounts are contract adjustments resulting from rework issues related to the manufacture of non-nuclear components being produced within our Nuclear Operations Group segment. We have recognized decreases in operating income of $26.7 million and $29.2 million for the three and nine months ended September 30, 2018, respectively, related to this matter. These contract adjustments resulted in a decrease in earnings per share of $0.21 and $0.23 for the three and nine months ended September 30, 2018, respectively.

Contract Assets and Liabilities

We include revenues and related costs incurred, plus accumulated contract costs that exceed amounts invoiced to customers under the terms of the contracts, in Contracts in progress. We include in Advance billings on contracts billings that exceed accumulated contract costs and revenues and costs recognized over time. Most long-term contracts contain provisions for progress payments. Our unbilled receivables do not contain an allowance for credit losses as we expect to invoice customers and collect all amounts for unbilled revenues. Changes in Contracts in progress and Advance billings on contracts are primarily driven by differences in the timing of revenue recognition and billings to our customers. During the nine months ended September 30, 2018, our unbilled receivables increased $66.0 million, primarily as a result of revenue in excess of billings on certain firm-fixed-price contracts within our Nuclear Operations Group segment and the timing of milestone billings on large components and contracts started in 2018 within our Nuclear Power Group segment. Our fixed-price incentive fee contracts for our Nuclear Operations Group segment include provisions that result in an increase in retainages on contracts during the first and third quarters of the year, with larger payments made during the second and fourth quarters. Retainages also vary as a result of timing differences between incurring costs and achieving milestones that allow us to recover these amounts. This resulted in an increase in retainages on contracts from January 1 to September 30, 2018 as shown below:



	September 30,		January 1,
	2018		2018
	(In thousands)
Included in Contracts in progress:
Unbilled receivables	$	316,341	$	250,325
Included in Accounts receivable – trade, net:
Retainages	$	102,555	$	82,801
Included in Other Assets:
Retainages	$	1,626	$	1,669
Advance billings on contracts	$	104,646	$	73,390

During the nine months ended September 30, 2018, we recognized $49.0 million of revenue that was in Advance billings on contracts at January 1, 2018.

Remaining Performance Obligations

Remaining performance obligations represent the dollar amount of revenue we expect to recognize in the future from performance obligations on contracts previously awarded and in progress. Of the September 30, 2018 remaining performance obligations on our contracts with customers, we expect to recognize revenues as follows:



	2018		2019		Thereafter		Total
	(In approximate millions)
Nuclear Operations Group	$	304	$	889	$	1,747	$	2,940
Nuclear Services Group	18		3		5		26
Nuclear Power Group	84		176		608		868
Total Remaining Performance Obligations	$	406	$	1,068	$	2,360	$	3,834

Historical Method

Prior to the adoption of FASB Topic Revenue from Contracts with Customers, we accounted for revenue under previous GAAP. In accordance with our adoption of the new revenue recognition standard utilizing the modified retrospective approach, we are required to disclose the impact on our financial statements on a line item basis.

A comparison of certain line items in our condensed consolidated balance sheet is shown below:



	September 30, 2018
	Current Method		Historical Method
	(In thousands)
Assets:
Contracts in progress	$	326,355	$	352,389
Deferred Income Taxes	$	45,105	$	46,785
Liabilities:
Accrued liabilities – other	$	53,508	$	50,435
Advance billings on contracts	$	104,646	$	150,081
Stockholders' Equity:
Retained earnings	$	1,159,552	$	1,144,904

Differences in the amounts above are primarily the result of the initial adoption of the new revenue recognition standard. Additional differences were caused by revenue under the current method being $8.5 million higher than the historical method as discussed below.

A comparison of certain line items in our condensed consolidated statements of income is shown below:



	Three Months Ended September 30, 2018				Nine Months Ended September 30, 2018
	Current Method		Historical Method		Current Method		Historical Method
	(In thousands)
Revenues	$	425,507	$	407,759	$	1,321,891	$	1,313,392
Cost of operations	$	326,314	$	315,196	$	971,887	$	969,683
Operating Income	$	50,395	$	43,765	$	201,832	$	195,537
Provision for Income Taxes	$	6,482	$	4,962	$	43,578	$	42,005
Net Income	$	78,077	$	72,967	$	205,224	$	200,502

We recognized $17.7 million and $8.5 million more revenue under the current method compared to the historical method for the three and nine months ended September 30, 2018, respectively. This was primarily driven by more progress being achieved on contracts as a result of using a cost-to-cost method for measuring progress under the current method as compared to man-hours or units of output under our historical method.

Pension Plans and Postretirement Benefits

9 Months Ended

Sep. 30, 2018

Defined Benefit Plan [Abstract]

Pension Plans and Postretirement Benefits

PENSION PLANS AND POSTRETIREMENT BENEFITS

We record the service cost component of net periodic benefit cost within Operating income on our condensed consolidated statements of income. For the three months ended September 30, 2018 and 2017, these amounts were $2.5 million and $1.8 million, respectively. For the nine months ended September 30, 2018 and 2017, these amounts were $7.7 million and $6.4 million, respectively. All other components of net periodic benefit cost are included in Other – net within the condensed consolidated statements of income. For the three months ended September 30, 2018 and 2017, these amounts were $(42.4) million and $(6.9) million, respectively. For the nine months ended September 30, 2018 and 2017, these amounts were $(60.1) million and $(20.8) million, respectively. Components of net periodic benefit cost included in net income are as follows:



	Pension Benefits												Other Benefits
	Three Months Ended September 30,						Nine Months Ended September 30,						Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017			2018			2017			2018			2017
	(In thousands)
Service cost	$	2,380		$	1,721		$	7,198		$	6,017		$	132		$	116		$	459		$	423
Interest cost	11,575			13,727			36,225			40,735			504			557			1,404			1,635
Expected return on plan assets	(19,272		)	(21,019		)	(62,450		)	(62,659		)	(548		)	(596		)	(1,581		)	(1,787		)
Amortization of prior service cost (credit)	565			506			1,665			1,556			(127		)	(79		)	(234		)	(236		)
Recognized net actuarial gain	(35,130		)	—			(35,130		)	—			—			—			—			—
Net periodic benefit (income) cost	$	(39,882	)	$	(5,065	)	$	(52,492	)	$	(14,351	)	$	(39	)	$	(2	)	$	48		$	35

We immediately recognize net actuarial gains and losses for our pension and postretirement benefit plans into earnings as a component of net periodic benefit cost. In July 2018, we completed the purchase of a group annuity contract to transfer certain domestic pension benefit obligations of $244.1 million to an insurance company for approximately 1,300 retirees. As a result, we remeasured two of our domestic pension plans resulting in the recognition of a net actuarial gain of $35.1 million in Other – net within the condensed consolidated statement of income, which includes a $10.4 million settlement loss and a $45.5 million actuarial gain.

We made contributions to our pension and postretirement plans totaling $157.9 million during the nine months ended September 30, 2018. In August 2018, we accelerated $118.1 million of pension contributions to certain domestic pension plans in order to capture a tax benefit in our 2017 U.S. tax return due to the change in corporate tax rates. For the remainder of 2018, we expect cash requirements totaling approximately $3.6 million for contributions to our pension and other postretirement benefit plans.

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Other than as noted below, there have been no material changes during the period covered by this Form 10-Q in the status of the legal proceedings disclosed in Note 10 to the consolidated financial statements in Part II of our 2017 10-K. Investigations and Litigation Apollo and Parks Township In January 2010, Michelle McMunn, Cara D. Steele and Yvonne Sue Robinson filed suit against Babcock & Wilcox Power Generation Group, Inc. ("B&W PGG"), Babcock & Wilcox Technical Services Group, Inc., formerly known as B&W Nuclear Environmental Services, Inc. and now known as BWXT Technical Services Group, Inc. (the "BWXT Parties") and Atlantic Richfield Company ("ARCO") in the U.S. District Court for the Western District of Pennsylvania. Since January 2010, additional suits were filed by additional plaintiffs and there were 17 lawsuits pending in the U.S. District Court for the Western District of Pennsylvania (the "Trial Court") against the BWXT Parties and ARCO, including the most recent lawsuits filed in June and October 2015. In total, the suits involved approximately 107 primary claimants. The primary claimants alleged, among other things, personal injuries and property damage as a result of alleged releases of radioactive material relating to the operation, remediation and/or decommissioning of two former nuclear fuel processing facilities located in the Borough of Apollo and Parks Township, Pennsylvania (collectively, the "Apollo and Parks Litigation"). Those facilities previously were owned by Nuclear Materials and Equipment Company, a former subsidiary of ARCO ("NUMEC"), which was acquired by B&W PGG. The plaintiffs in the Apollo and Parks Litigation sought compensatory and punitive damages. Between May 2015 and March 2016, the presiding judge in the Apollo and Parks Litigation granted the BWXT Parties' motions to dismiss or motions for summary judgment in all 17 of the existing lawsuits. Accordingly, all claims in the Apollo and Parks Litigation have been dismissed by the Trial Court. All plaintiffs filed notices of appeal, and the appeals were consolidated in the U.S. Court of Appeals for the Third Circuit (the "Court of Appeals"). On August 23, 2017, the Court of Appeals affirmed the rulings of the Trial Court, dismissing all claims against the BWXT Parties and other defendants in the cases. Plaintiffs filed a notice of petition for rehearing, which was denied by the Court of Appeals on September 21, 2017. The plaintiffs filed a writ of certiorari for review by the U.S. Supreme Court on December 20, 2017. On February 20, 2018, the U.S. Supreme Court denied plaintiffs' petition for writ of certiorari making the Court of Appeals decision affirming the dismissal of all 17 lawsuits final. At the time of ARCO's sale of NUMEC stock to B&W PGG, B&W PGG received an indemnity and hold harmless agreement from ARCO, which has been assigned to BWXT and its affiliates, with respect to claims and liabilities arising prior to or as a result of conduct or events predating the acquisition. The ARCO indemnity remains applicable should any future claims similar in nature to the Apollo and Parks Litigation be made, although no assurance can be given that the indemnity will be available or sufficient in the event of liability, if any.

Derivative Financial Instruments

9 Months Ended

Sep. 30, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Financial Instruments

DERIVATIVE FINANCIAL INSTRUMENTS

Our operations give rise to exposure to market risks from changes in foreign currency exchange ("FX") rates. We use derivative financial instruments, primarily FX forward contracts, to reduce the impact of changes in FX rates on our operating results. We use these instruments primarily to hedge our exposure associated with revenues or costs on our long-term contracts that are denominated in currencies other than our operating entities' functional currencies. In addition, we have entered into FX forward contracts to hedge our exposure on pending acquisitions. We do not hold or issue derivative financial instruments for trading or other speculative purposes.

We enter into derivative financial instruments primarily as hedges of certain firm purchase and sale commitments denominated in foreign currencies. We record these contracts at fair value on our condensed consolidated balance sheets. Based on the hedge designation at the inception of the contract, the related gains and losses on these contracts are deferred in stockholders' equity as a component of Accumulated other comprehensive income until the hedged item is recognized in earnings. Any ineffective portion of a derivative's change in fair value and any portion excluded from the assessment of effectiveness are immediately recognized in Other – net in our condensed consolidated statements of income. The gain or loss on a derivative instrument not designated as a hedging instrument is also immediately recognized in earnings. Gains and losses on derivative financial instruments that require immediate recognition are included as a component of Other – net in our condensed consolidated statements of income.

We have designated the majority of our FX forward contracts that qualify for hedge accounting as cash flow hedges. The hedged risk is the risk of changes in functional-currency-equivalent cash flows attributable to changes in FX spot rates of forecasted transactions related to long-term contracts. We exclude from our assessment of effectiveness the portion of the fair value of the FX forward contracts attributable to the difference between FX spot rates and FX forward rates. At September 30, 2018, we had deferred approximately $0.3 million of net gains on these derivative financial instruments in Accumulated other comprehensive income. Assuming market conditions continue, we expect to recognize the majority of this amount in the next 12 months.

At September 30, 2018, our derivative financial instruments consisted of FX forward contracts. The notional value of our FX forward contracts totaled $49.0 million at September 30, 2018, with maturities extending to December 2021. These instruments consist primarily of contracts to purchase or sell Canadian dollars. We are exposed to credit-related losses in the event of non-performance by counterparties to derivative financial instruments. We attempt to mitigate this risk by using major financial institutions with high credit ratings. Our counterparties have the benefit of the same collateral arrangements and covenants as described under our credit facility.

The following tables summarize our derivative financial instruments at September 30, 2018 and December 31, 2017:



	Asset and Liability Derivatives
	September 30, 2018		December 31, 2017
	(In thousands)
Derivatives Designated as Hedges:
FX Forward Contracts:
Location
Accounts receivable – other	$	218	$	250
Other Assets	$	211	$	348
Accounts payable	$	120	$	177
Other Liabilities	$	152	$	93

The effects of derivatives on our financial statements are outlined below:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
	(In thousands)
Derivatives Designated as Hedges:
Cash Flow Hedges:
FX Forward Contracts:
Amount of gain (loss) recognized in other comprehensive income	$	(63	)	$	(349	)	$	12		$	578
Gain (loss) reclassified from accumulated other comprehensive income (loss) into earnings: effective portion
Location
Revenues	$	(86	)	$	195		$	(90	)	$	182
Cost of operations	$	119		$	(470	)	$	147		$	(179	)
Derivatives Not Designated as Hedges:
FX Forward Contracts:
Gain (loss) recognized in income
Location
Other – net	$	(1,254	)	$	—		$	4,743		$	—

Fair Value Measurements

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurements

FAIR VALUE MEASUREMENTS

Investments

The following is a summary of our investments measured at fair value at September 30, 2018:



	Total		Level 1		Level 2		Level 3
	(In thousands)
Equity securities
Equities	$	1,851	$	—	$	1,851	$	—
Mutual funds	5,170		—		5,170		—
Available-for-sale securities
U.S. Government and agency securities	1,982		1,982		—		—
Corporate bonds	2,228		1,479		749		—
Asset-backed securities and collateralized mortgage obligations	105		—		105		—
Total	$	11,336	$	3,461	$	7,875	$	—

The following is a summary of our investments measured at fair value at December 31, 2017:



	Total		Level 1		Level 2		Level 3
	(In thousands)
Available-for-sale securities
U.S. Government and agency securities	$	1,299	$	1,299	$	—	$	—
Corporate bonds	3,169		1,534		1,635		—
Equities	2,759		—		2,759		—
Mutual funds	4,847		—		4,847		—
Asset-backed securities and collateralized mortgage obligations	161		—		161		—
Total	$	12,235	$	2,833	$	9,402	$	—

We estimate the fair value of investments based on quoted market prices. For investments for which there are no quoted market prices, we derive fair values from available yield curves for investments of similar quality and terms.

Derivatives

Level 2 derivative assets and liabilities currently consist of FX forward contracts. Where applicable, the value of these derivative assets and liabilities is computed by discounting the projected future cash flow amounts to present value using market-based observable inputs, including FX forward and spot rates, interest rates and counterparty performance risk adjustments. At September 30, 2018 and December 31, 2017, we had forward contracts outstanding to purchase or sell Canadian dollars, with a total fair value of $0.2 million and $0.3 million, respectively.

Other Financial Instruments

We used the following methods and assumptions in estimating our fair value disclosures for our other financial instruments, as follows:

Cash and cash equivalents and restricted cash and cash equivalents. The carrying amounts that we have reported in the accompanying condensed consolidated balance sheets for Cash and cash equivalents and Restricted cash and cash equivalents approximate their fair values due to their highly liquid nature.

Long-term and short-term debt. We base the fair values of debt instruments on quoted market prices. Where quoted prices are not available, we base the fair values on the present value of future cash flows discounted at estimated borrowing rates for similar debt instruments or on estimated prices based on current yields for debt issues of similar quality and terms. The fair values of our debt instruments approximated their carrying values at September 30, 2018 and December 31, 2017.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Stock-Based Compensation	9 Months Ended
Stock-Based Compensation	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION Stock-based compensation recognized for all of our plans for the three months ended September 30, 2018 and 2017 totaled $2.8 million and $3.9 million, respectively, with associated tax benefit totaling $0.5 million and $1.4 million, respectively. Stock-based compensation recognized for all of our plans for the nine months ended September 30, 2018 and 2017 totaled $9.1 million and $12.6 million, respectively, with associated tax benefit totaling $1.7 million and $4.4 million, respectively.

Segment Reporting

9 Months Ended

Sep. 30, 2018

Segment Reporting [Abstract]

Segment Reporting

SEGMENT REPORTING

As described in Note 1, our operations are assessed based on three reportable segments. An analysis of our operations by reportable segment is as follows:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
	(In thousands)
REVENUES:
Nuclear Operations Group	$	319,325		$	324,545		$	968,096		$	962,492
Nuclear Services Group	28,366			27,507			90,995			100,146
Nuclear Power Group	79,162			68,621			267,675			200,864
Adjustments and Eliminations ⁽¹⁾	(1,346		)	(1,313		)	(4,875		)	(5,902		)
	$	425,507		$	419,360		$	1,321,891		$	1,257,600


(1)	Segment revenues are net of the following intersegment transfers and other adjustments:



Nuclear Operations Group Transfers	$	(978	)	$	(192	)	$	(2,958	)	$	(592	)
Nuclear Services Group Transfers	(273		)	(1,043		)	(1,813		)	(5,113		)
Nuclear Power Group Transfers	(95		)	(78		)	(104		)	(197		)
	$	(1,346	)	$	(1,313	)	$	(4,875	)	$	(5,902	)
OPERATING INCOME:
Nuclear Operations Group	$	45,580		$	66,459		$	180,283		$	203,503
Nuclear Services Group	6,494			776			11,182			16,577
Nuclear Power Group	9,063			8,426			38,637			27,094
Other	(5,142		)	(2,255		)	(13,542		)	(4,937		)
	$	55,995		$	73,406		$	216,560		$	242,237
Unallocated Corporate ⁽²⁾	(5,600		)	(6,629		)	(14,728		)	(13,760		)
Total Operating Income	$	50,395		$	66,777		$	201,832		$	228,477
Other Income (Expense):
Interest income	1,121			402			2,340			750
Interest expense	(7,925		)	(3,837		)	(19,354		)	(11,260		)
Other – net	40,968			7,252			63,984			21,487
Total Other Income (Expense)	34,164			3,817			46,970			10,977
Income before Provision for Income Taxes	$	84,559		$	70,594		$	248,802		$	239,454


(2)	Unallocated corporate includes general corporate overhead not allocated to segments.

Earnings Per Share

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Earnings Per Share

EARNINGS PER SHARE

The following table sets forth the computation of basic and diluted earnings per share:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
	(In thousands, except share and per share amounts)
Basic:
Net Income Attributable to BWX Technologies, Inc.	$	77,919	$	46,553	$	205,023	$	163,534
Weighted-average common shares	99,421,031		99,328,677		99,542,933		99,313,264
Basic earnings per common share	$	0.78	$	0.47	$	2.06	$	1.65
Diluted:
Net Income Attributable to BWX Technologies, Inc.	$	77,919	$	46,553	$	205,023	$	163,534
Weighted-average common shares (basic)	99,421,031		99,328,677		99,542,933		99,313,264
Effect of dilutive securities:
Stock options, restricted stock units and performance shares ⁽¹⁾	999,735		931,578		958,664		1,054,119
Adjusted weighted-average common shares	100,420,766		100,260,255		100,501,597		100,367,383
Diluted earnings per common share	$	0.78	$	0.46	$	2.04	$	1.63


(1)	At September 30, 2018 and 2017, none of our shares were antidilutive.

Basis of Presentation and Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Basis of Presentation

Consolidation

Unless the context otherwise indicates, "we," "us" and "our" mean BWXT and its consolidated subsidiaries.

Reportable Segments

We operate in three reportable segments: Nuclear Operations Group, Nuclear Services Group and Nuclear Power Group. Our reportable segments are further described as follows:

•

Contracts and Revenue Recognition

Inventories

At September 30, 2018 and December 31, 2017, Other current assets included inventories totaling $15.5 million and $8.6 million, respectively, consisting entirely of raw materials and supplies.

Restricted Cash and Cash Equivalents

Warranty Expense

Provision for Income Taxes

New Accounting Standards

Basis of Presentation and Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Components of Accumulated Other Comprehensive Income

The components of Accumulated other comprehensive income included in Stockholders' Equity are as follows:



	September 30, 2018			December 31, 2017
	(In thousands)
Currency translation adjustments	$	8,423		$	13,148
Net unrealized gain on derivative financial instruments	319			353
Unrecognized prior service cost on benefit obligations	(5,092		)	(6,237		)
Net unrealized gain (loss) on available-for-sale investments	(108		)	2,190
Accumulated other comprehensive income	$	3,542		$	9,454

Schedule of Amounts Reclassified from Accumulated Other Comprehensive Income

The amounts reclassified out of Accumulated other comprehensive income by component and the affected condensed consolidated statements of income line items are as follows:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
Accumulated Other Comprehensive Income (Loss) Component Recognized	(In thousands)												Line Item Presented
Realized gain (loss) on derivative financial instruments	$	(86	)	$	195		$	(90	)	$	182		Revenues
	119			(470		)	147			(179		)	Cost of operations
	33			(275		)	57			3			Total before tax
	(7		)	71			(16		)	—			Provision for Income Taxes
	$	26		$	(204	)	$	41		$	3		Net Income
Amortization of prior service cost on benefit obligations	$	(438	)	$	(428	)	$	(1,431	)	$	(1,320	)	Other – net
	78			146			286			459			Provision for Income Taxes
	$	(360	)	$	(282	)	$	(1,145	)	$	(861	)	Net Income
Realized gain (loss) on investments	$	(354	)	$	14		$	(354	)	$	162		Other – net
	(25		)	(5		)	(25		)	(19		)	Provision for Income Taxes
	$	(379	)	$	9		$	(379	)	$	143		Net Income
Total reclassification for the period	$	(713	)	$	(477	)	$	(1,483	)	$	(715	)

Restricted Cash and Cash Equivalents



	September 30, 2018		December 31, 2017
	(In thousands)
Cash and cash equivalents	$	66,125	$	203,404
Restricted cash and cash equivalents	4,359		7,105
Restricted cash and cash equivalents included in Other Assets	2,638		2,635
Total cash and cash equivalents and restricted cash and cash equivalents as presented in our condensed consolidated statement of cash flows	$	73,122	$	213,144

Restricted Cash and Cash Equivalents



	September 30, 2018		December 31, 2017
	(In thousands)
Cash and cash equivalents	$	66,125	$	203,404
Restricted cash and cash equivalents	4,359		7,105
Restricted cash and cash equivalents included in Other Assets	2,638		2,635
Total cash and cash equivalents and restricted cash and cash equivalents as presented in our condensed consolidated statement of cash flows	$	73,122	$	213,144

Summary of Changes in Carrying Amount of Accrued Warranty Expense

The following summarizes the changes in the carrying amount of our Accrued warranty expense:



	Nine Months Ended September 30,
	2018			2017
	(In thousands)
Balance at beginning of period	$	13,428		$	11,477
Additions	1,136			1,011
Expirations and other changes	(1,400		)	(188		)
Payments	(482		)	(21		)
Translation	(256		)	434
Balance at end of period	$	12,426		$	12,713

Acquisitions (Tables)

9 Months Ended

Sep. 30, 2018

Business Combinations [Abstract]

Schedule of Business Acquisition Assets Acquired and Liabilities Assumed

Our preliminary purchase price allocation, as follows, is subject to change upon receipt of additional information and completion of further analysis, including, but not limited to, finalization of valuations related to long-lived and intangible assets (amounts in thousands):



Accounts receivable – trade	$	7,732
Contracts in progress	51
Inventories	2,113
Other current assets	97
Property, plant and equipment	12,948
Goodwill	62,495
Deferred Income Taxes	3,006
Intangible assets	139,257
Total assets acquired	$	227,699
Accounts payable	$	654
Accrued employee benefits	579
Accrued liabilities – other	1,665
Environmental liabilities	2,062
Pension liability	9,746
Total liabilities assumed	$	14,706
Net assets acquired	$	212,993
Amount of tax deductible goodwill	$	53,693

Schedule of Intangible Assets Acquired

The intangible assets included above consist of the following (dollar amounts in thousands):



	Amount		Amortization Period
Technical support agreement and relationship	$	67,500	23 years
Unpatented technology	$	33,000	19 years
Favorable operating leases	$	28,157	13-30 years
Customer relationship	$	10,600	19 years

Schedule of Unaudited Pro Forma Financial Information

This information is presented for comparative purposes only and should not be taken as representative of our future consolidated results of operations.



	Three Months Ended				Nine Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
	(In thousands, except per share amounts)
Revenues	$	429,558	$	429,791	$	1,347,031	$	1,285,536
Net Income Attributable to BWX Technologies, Inc.	$	79,141	$	45,788	$	206,435	$	159,499
Basic Earnings per Common Share	$	0.80	$	0.46	$	2.07	$	1.61
Diluted Earnings per Common Share	$	0.79	$	0.46	$	2.05	$	1.59

Revenue Recognition (Tables)

9 Months Ended

Sep. 30, 2018

Revenue from Contract with Customer [Abstract]

Schedule of Initial Impact of the New Revenue Recognition Standard

A comparison of certain line items in our condensed consolidated balance sheet is shown below:



	September 30, 2018
	Current Method		Historical Method
	(In thousands)
Assets:
Contracts in progress	$	326,355	$	352,389
Deferred Income Taxes	$	45,105	$	46,785
Liabilities:
Accrued liabilities – other	$	53,508	$	50,435
Advance billings on contracts	$	104,646	$	150,081
Stockholders' Equity:
Retained earnings	$	1,159,552	$	1,144,904

The initial impact of the adoption of the FASB Topic Revenue from Contracts with Customers, which was recognized in a cumulative catch-up adjustment on January 1, 2018, is illustrated below:



	January 1,		December 31,
	2018		2017
	(In thousands)
Assets:
Contracts in progress	$	260,932	$	420,628
Deferred Income Taxes	$	85,193	$	86,740
Liabilities:
Accrued liabilities – other	$	66,371	$	64,738
Advance billings on contracts	$	73,390	$	246,192
Stockholders' Equity:
Retained earnings	$	1,000,578	$	990,652

A comparison of certain line items in our condensed consolidated statements of income is shown below:



	Three Months Ended September 30, 2018				Nine Months Ended September 30, 2018
	Current Method		Historical Method		Current Method		Historical Method
	(In thousands)
Revenues	$	425,507	$	407,759	$	1,321,891	$	1,313,392
Cost of operations	$	326,314	$	315,196	$	971,887	$	969,683
Operating Income	$	50,395	$	43,765	$	201,832	$	195,537
Provision for Income Taxes	$	6,482	$	4,962	$	43,578	$	42,005
Net Income	$	78,077	$	72,967	$	205,224	$	200,502

Schedule of Disaggregated Revenues

Revenues by geographical area and customer type are as follows:



	Three Months Ended September 30, 2018									Nine Months Ended September 30, 2018
	Nuclear Operations Group		Nuclear Services Group		Nuclear Power Group		Total			Nuclear Operations Group		Nuclear Services Group		Nuclear Power Group		Total
	(In thousands)
United States:
Government	$	315,744	$	27,120	$	—	$	342,864		$	960,271	$	81,175	$	—	$	1,041,446
Non-Government	2,066		536		3,890		6,492			5,915		7,623		4,477		18,015
	$	317,810	$	27,656	$	3,890	$	349,356		$	966,186	$	88,798	$	4,477	$	1,059,461
Canada:
Government	$	358	$	—	$	—	$	358		$	358	$	—	$	—	$	358
Non-Government	161		611		65,234		66,006			161		2,096		212,302		214,559
	$	519	$	611	$	65,234	$	66,364		$	519	$	2,096	$	212,302	$	214,917
Other:
Government	$	—	$	—	$	—	$	—		$	—	$	—	$	—	$	—
Non-Government	996		99		10,038		11,133			1,391		101		50,896		52,388
	$	996	$	99	$	10,038	$	11,133		$	1,391	$	101	$	50,896	$	52,388
Segment Revenues	$	319,325	$	28,366	$	79,162	426,853			$	968,096	$	90,995	$	267,675	1,326,766
Adjustments and Eliminations							(1,346		)							(4,875		)
Revenues							$	425,507								$	1,321,891

Revenues by timing of transfer of goods or services are as follows:



	Three Months Ended September 30, 2018									Nine Months Ended September 30, 2018
	Nuclear Operations Group		Nuclear Services Group		Nuclear Power Group		Total			Nuclear Operations Group		Nuclear Services Group		Nuclear Power Group		Total
	(In thousands)
Over-time	$	319,325	$	28,366	$	66,219	$	413,910		$	968,096	$	90,995	$	240,652	$	1,299,743
Point-in-time	—		—		12,943		12,943			—		—		27,023		27,023
Segment Revenues	$	319,325	$	28,366	$	79,162	426,853			$	968,096	$	90,995	$	267,675	1,326,766
Adjustments and Eliminations							(1,346		)							(4,875		)
Revenues							$	425,507								$	1,321,891

Revenues by contract type are as follows:



	Three Months Ended September 30, 2018									Nine Months Ended September 30, 2018
	Nuclear Operations Group		Nuclear Services Group		Nuclear Power Group		Total			Nuclear Operations Group		Nuclear Services Group		Nuclear Power Group		Total
	(In thousands)
Fixed-Price Incentive Fee	$	255,944	$	—	$	3,748	$	259,692		$	763,334	$	—	$	13,365	$	776,699
Firm-Fixed-Price	38,262		4,393		58,451		101,106			137,792		15,435		177,035		330,262
Cost-Plus Fee	25,117		23,496		—		48,613			66,800		73,535		45		140,380
Time-and-Materials	2		477		16,963		17,442			170		2,025		77,230		79,425
Segment Revenues	$	319,325	$	28,366	$	79,162	426,853			$	968,096	$	90,995	$	267,675	1,326,766
Adjustments and Eliminations							(1,346		)							(4,875		)
Revenues							$	425,507								$	1,321,891

Schedule of Contract Assets and Liabilities

Our fixed-price incentive fee contracts for our Nuclear Operations Group segment include provisions that result in an increase in retainages on contracts during the first and third quarters of the year, with larger payments made during the second and fourth quarters. Retainages also vary as a result of timing differences between incurring costs and achieving milestones that allow us to recover these amounts. This resulted in an increase in retainages on contracts from January 1 to September 30, 2018 as shown below:



	September 30,		January 1,
	2018		2018
	(In thousands)
Included in Contracts in progress:
Unbilled receivables	$	316,341	$	250,325
Included in Accounts receivable – trade, net:
Retainages	$	102,555	$	82,801
Included in Other Assets:
Retainages	$	1,626	$	1,669
Advance billings on contracts	$	104,646	$	73,390

Schedule of Remaining Performance Obligations

Of the September 30, 2018 remaining performance obligations on our contracts with customers, we expect to recognize revenues as follows:



	2018		2019		Thereafter		Total
	(In approximate millions)
Nuclear Operations Group	$	304	$	889	$	1,747	$	2,940
Nuclear Services Group	18		3		5		26
Nuclear Power Group	84		176		608		868
Total Remaining Performance Obligations	$	406	$	1,068	$	2,360	$	3,834

Pension Plans and Postretirement Benefits (Tables)

9 Months Ended

Sep. 30, 2018

Defined Benefit Plan [Abstract]

Components of Net Periodic Benefit Cost

Components of net periodic benefit cost included in net income are as follows:



	Pension Benefits												Other Benefits
	Three Months Ended September 30,						Nine Months Ended September 30,						Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017			2018			2017			2018			2017
	(In thousands)
Service cost	$	2,380		$	1,721		$	7,198		$	6,017		$	132		$	116		$	459		$	423
Interest cost	11,575			13,727			36,225			40,735			504			557			1,404			1,635
Expected return on plan assets	(19,272		)	(21,019		)	(62,450		)	(62,659		)	(548		)	(596		)	(1,581		)	(1,787		)
Amortization of prior service cost (credit)	565			506			1,665			1,556			(127		)	(79		)	(234		)	(236		)
Recognized net actuarial gain	(35,130		)	—			(35,130		)	—			—			—			—			—
Net periodic benefit (income) cost	$	(39,882	)	$	(5,065	)	$	(52,492	)	$	(14,351	)	$	(39	)	$	(2	)	$	48		$	35

Derivative Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Summary of Derivative Financial Instruments

The following tables summarize our derivative financial instruments at September 30, 2018 and December 31, 2017:



	Asset and Liability Derivatives
	September 30, 2018		December 31, 2017
	(In thousands)
Derivatives Designated as Hedges:
FX Forward Contracts:
Location
Accounts receivable – other	$	218	$	250
Other Assets	$	211	$	348
Accounts payable	$	120	$	177
Other Liabilities	$	152	$	93

Schedule of Effect of Derivative Instruments on Financial Statements

The effects of derivatives on our financial statements are outlined below:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
	(In thousands)
Derivatives Designated as Hedges:
Cash Flow Hedges:
FX Forward Contracts:
Amount of gain (loss) recognized in other comprehensive income	$	(63	)	$	(349	)	$	12		$	578
Gain (loss) reclassified from accumulated other comprehensive income (loss) into earnings: effective portion
Location
Revenues	$	(86	)	$	195		$	(90	)	$	182
Cost of operations	$	119		$	(470	)	$	147		$	(179	)
Derivatives Not Designated as Hedges:
FX Forward Contracts:
Gain (loss) recognized in income
Location
Other – net	$	(1,254	)	$	—		$	4,743		$	—

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Summary of Investments Measured at Fair Value

The following is a summary of our investments measured at fair value at September 30, 2018:



	Total		Level 1		Level 2		Level 3
	(In thousands)
Equity securities
Equities	$	1,851	$	—	$	1,851	$	—
Mutual funds	5,170		—		5,170		—
Available-for-sale securities
U.S. Government and agency securities	1,982		1,982		—		—
Corporate bonds	2,228		1,479		749		—
Asset-backed securities and collateralized mortgage obligations	105		—		105		—
Total	$	11,336	$	3,461	$	7,875	$	—

The following is a summary of our investments measured at fair value at December 31, 2017:



	Total		Level 1		Level 2		Level 3
	(In thousands)
Available-for-sale securities
U.S. Government and agency securities	$	1,299	$	1,299	$	—	$	—
Corporate bonds	3,169		1,534		1,635		—
Equities	2,759		—		2,759		—
Mutual funds	4,847		—		4,847		—
Asset-backed securities and collateralized mortgage obligations	161		—		161		—
Total	$	12,235	$	2,833	$	9,402	$	—

Segment Reporting (Tables)

9 Months Ended

Sep. 30, 2018

Segment Reporting [Abstract]

Schedule of Operating Results by Segment

An analysis of our operations by reportable segment is as follows:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
	(In thousands)
REVENUES:
Nuclear Operations Group	$	319,325		$	324,545		$	968,096		$	962,492
Nuclear Services Group	28,366			27,507			90,995			100,146
Nuclear Power Group	79,162			68,621			267,675			200,864
Adjustments and Eliminations ⁽¹⁾	(1,346		)	(1,313		)	(4,875		)	(5,902		)
	$	425,507		$	419,360		$	1,321,891		$	1,257,600


(1)	Segment revenues are net of the following intersegment transfers and other adjustments:



Nuclear Operations Group Transfers	$	(978	)	$	(192	)	$	(2,958	)	$	(592	)
Nuclear Services Group Transfers	(273		)	(1,043		)	(1,813		)	(5,113		)
Nuclear Power Group Transfers	(95		)	(78		)	(104		)	(197		)
	$	(1,346	)	$	(1,313	)	$	(4,875	)	$	(5,902	)
OPERATING INCOME:
Nuclear Operations Group	$	45,580		$	66,459		$	180,283		$	203,503
Nuclear Services Group	6,494			776			11,182			16,577
Nuclear Power Group	9,063			8,426			38,637			27,094
Other	(5,142		)	(2,255		)	(13,542		)	(4,937		)
	$	55,995		$	73,406		$	216,560		$	242,237
Unallocated Corporate ⁽²⁾	(5,600		)	(6,629		)	(14,728		)	(13,760		)
Total Operating Income	$	50,395		$	66,777		$	201,832		$	228,477
Other Income (Expense):
Interest income	1,121			402			2,340			750
Interest expense	(7,925		)	(3,837		)	(19,354		)	(11,260		)
Other – net	40,968			7,252			63,984			21,487
Total Other Income (Expense)	34,164			3,817			46,970			10,977
Income before Provision for Income Taxes	$	84,559		$	70,594		$	248,802		$	239,454


(2)	Unallocated corporate includes general corporate overhead not allocated to segments.

Earnings Per Share (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Computation of Basic and Diluted Earnings Per Share

The following table sets forth the computation of basic and diluted earnings per share:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
	(In thousands, except share and per share amounts)
Basic:
Net Income Attributable to BWX Technologies, Inc.	$	77,919	$	46,553	$	205,023	$	163,534
Weighted-average common shares	99,421,031		99,328,677		99,542,933		99,313,264
Basic earnings per common share	$	0.78	$	0.47	$	2.06	$	1.65
Diluted:
Net Income Attributable to BWX Technologies, Inc.	$	77,919	$	46,553	$	205,023	$	163,534
Weighted-average common shares (basic)	99,421,031		99,328,677		99,542,933		99,313,264
Effect of dilutive securities:
Stock options, restricted stock units and performance shares ⁽¹⁾	999,735		931,578		958,664		1,054,119
Adjusted weighted-average common shares	100,420,766		100,260,255		100,501,597		100,367,383
Diluted earnings per common share	$	0.78	$	0.46	$	2.04	$	1.63


(1)	At September 30, 2018 and 2017, none of our shares were antidilutive.

Basis of Presentation and Significant Accounting Policies - Additional Information (Details) $ in Thousands			3 Months Ended		9 Months Ended
	Jul. 30, 2018 USD ($) Facilities employee	Mar. 02, 2016 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) component segment	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Basis Of Presentation And Significant Accounting Policies [Line Items]
Number of reportable segments \| segment					3
Number of components supplied to worldwide (more than) \| component					1,300
Accumulated other comprehensive income			$ (3,542)		$ (3,542)		$ (9,454)
Total inventories			15,500		15,500		8,600
Restricted cash and cash equivalents			$ 7,000		$ 7,000
Effective tax rate			7.70%	33.90%	17.50%	31.60%
Effective income tax rate reconciliation, share-based compensation cost (benefit) amount						$ (5,400)
Gross unrecognized tax benefits			$ 300		$ 300
Increase in cash and cash equivalents and restricted cash and cash equivalents			73,122	$ 213,210	73,122	$ 213,210	213,144	$ 134,600
Accounting Standards Update 2016-01
Basis Of Presentation And Significant Accounting Policies [Line Items]
Accumulated other comprehensive income							$ 2,200
Cash Held for Future Decommissioning of Facilities
Basis Of Presentation And Significant Accounting Policies [Line Items]
Restricted cash and cash equivalents			2,600		2,600
Cash Held to Meet Reinsurance Reserve Requirements
Basis Of Presentation And Significant Accounting Policies [Line Items]
Restricted cash and cash equivalents			$ 4,400		$ 4,400
Unsuccessful Outcome of Framework Agreement
Basis Of Presentation And Significant Accounting Policies [Line Items]
Loss contingency as a result of the Framework Agreement		$ 30,000
Canada Revenue Agency
Basis Of Presentation And Significant Accounting Policies [Line Items]
Statutory tax rate for Canada operations					25.00%
Sotera Health LLC's Nordion Medical Isotope Business
Basis Of Presentation And Significant Accounting Policies [Line Items]
Business combination, consideration transferred	$ 213,000
Number of personnel acquired \| employee	150
Business acquisition, number of operating facilities \| Facilities	2

Basis of Presentation and Significant Accounting Policies - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Currency translation adjustments	$ 8,423	$ 13,148
Net unrealized gain on derivative financial instruments	319	353
Unrecognized prior service cost on benefit obligations	(5,092)	(6,237)
Net unrealized gain (loss) on available-for-sale investments	(108)	2,190
Accumulated other comprehensive income	$ 3,542	$ 9,454

Basis of Presentation and Significant Accounting Policies - Schedule of Amounts Reclassified from Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues	$ 425,507	$ 419,360	$ 1,321,891	$ 1,257,600
Cost of operations	(326,314)	(302,267)	(971,887)	(883,839)
Income before Provision for Income Taxes	84,559	70,594	248,802	239,454
Other – net	40,968	7,252	63,984	21,487
Provision for Income Taxes	(6,482)	(23,901)	(43,578)	(75,556)
Net Income	78,077	46,693	205,224	163,898
Accumulated Other Comprehensive Income (Loss) Component Recognized
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net Income	(713)	(477)	(1,483)	(715)
Accumulated Other Comprehensive Income (Loss) Component Recognized \| Realized gain (loss) on derivative financial instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenues	(86)	195	(90)	182
Cost of operations	119	(470)	147	(179)
Income before Provision for Income Taxes	33	(275)	57	3
Provision for Income Taxes	(7)	71	(16)	0
Net Income	26	(204)	41	3
Accumulated Other Comprehensive Income (Loss) Component Recognized \| Amortization of prior service cost on benefit obligations
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other – net	(438)	(428)	(1,431)	(1,320)
Provision for Income Taxes	78	146	286	459
Net Income	(360)	(282)	(1,145)	(861)
Accumulated Other Comprehensive Income (Loss) Component Recognized \| Realized gain (loss) on investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other – net	(354)	14	(354)	162
Provision for Income Taxes	(25)	(5)	(25)	(19)
Net Income	$ (379)	$ 9	$ (379)	$ 143

Basis of Presentation and Significant Accounting Policies - Reconciliation of Cash and Cash Equivalents and Restricted Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash and cash equivalents	$ 66,125	$ 203,404
Restricted cash and cash equivalents	4,359	7,105
Restricted cash and cash equivalents included in Other Assets	2,638	2,635
Total cash and cash equivalents and restricted cash and cash equivalents as presented in our condensed consolidated statement of cash flows	$ 73,122	$ 213,144	$ 213,210	$ 134,600

Basis of Presentation and Significant Accounting Policies - Summary of Changes in Carrying Amount of Accrued Warranty Expense (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Movement in Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 13,428	$ 11,477
Additions	1,136	1,011
Expirations and other changes	(1,400)	(188)
Payments	(482)	(21)
Translation	(256)	434
Balance at end of period	$ 12,426	$ 12,713

Acquisitions - Additional Information (Detail) - Sotera Health LLC's Nordion Medical Isotope Business $ in Millions		3 Months Ended		9 Months Ended
	Jul. 30, 2018 USD ($) Facilities employee	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)
Business Acquisition [Line Items]
Business combination, consideration transferred	$ 213.0
Number of personnel acquired \| employee	150
Business acquisition, number of operating facilities \| Facilities	2
Revenues related to medical isotope business operations		$ 8.0		$ 8.0
Net Income related to medical isotope business operations		0.5		0.5
Increase in Amortization Expense
Business Acquisition [Line Items]
Adjustment to value of intangible assets		0.5	$ 1.6	3.7	$ 4.8
Additional Interest Expense
Business Acquisition [Line Items]
Adjustment to interest expense			$ 1.4	2.4	$ 3.8
Elimination of Acquisition Related Costs
Business Acquisition [Line Items]
Acquisition related costs		$ 0.9		$ 2.5
Minimum \| Favorable operating leases
Business Acquisition [Line Items]
Amortization Period	13 years
Maximum \| Favorable operating leases
Business Acquisition [Line Items]
Amortization Period	30 years

Acquisitions - Business Acquisition Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Jul. 30, 2018	Dec. 31, 2017
Condensed Income Statements, Captions [Line Items]
Goodwill	$ 278,939		$ 218,331
Sotera Health LLC's Nordion Medical Isotope Business
Condensed Income Statements, Captions [Line Items]
Accounts receivable – trade		$ 7,732
Contracts in progress		51
Inventories		2,113
Other current assets		97
Property, plant and equipment		12,948
Goodwill		62,495
Deferred Income Taxes		3,006
Intangible assets		139,257
Total assets acquired		227,699
Accounts payable		654
Accrued employee benefits		579
Accrued liabilities – other		1,665
Environmental liabilities		2,062
Pension liability		9,746
Total liabilities assumed		14,706
Net assets acquired		212,993
Amount of tax deductible goodwill		$ 53,693

Acquisitions - Preliminary Intangible Assets Acquired (Detail) - Sotera Health LLC's Nordion Medical Isotope Business $ in Thousands	Jul. 30, 2018 USD ($)
Technical support agreement and relationship
Acquired Finite-Lived Intangible Assets [Line Items]
Amount	$ 67,500
Amortization Period	23 years
Unpatented technology
Acquired Finite-Lived Intangible Assets [Line Items]
Amount	$ 33,000
Amortization Period	19 years
Favorable operating leases
Acquired Finite-Lived Intangible Assets [Line Items]
Amount	$ 28,157
Customer relationship
Acquired Finite-Lived Intangible Assets [Line Items]
Amount	$ 10,600
Amortization Period	19 years

Acquisitions - Unaudited Pro Forma Financial Information (Detail) - Sotera Health LLC's Nordion Medical Isotope Business - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Revenues	$ 429,558	$ 429,791	$ 1,347,031	$ 1,285,536
Net Income Attributable to BWX Technologies, Inc.	$ 79,141	$ 45,788	$ 206,435	$ 159,499
Basic Earnings per Common Share (in usd per share)	$ 0.80	$ 0.46	$ 2.07	$ 1.61
Diluted Earnings per Common Share (in usd per share)	$ 0.79	$ 0.46	$ 2.05	$ 1.59

Revenue Recognition - Initial Impact of New Revenue Recognition Standard (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Assets
Contracts in progress	$ 326,355		$ 420,628
Deferred Income Taxes	45,105		86,740
Liabilities
Accrued liabilities – other	53,508		64,738
Advance billings on contracts	104,646		246,192
Stockholders' Equity
Retained earnings	1,159,552		990,652
Accounting Standards Update 2014-09
Assets
Contracts in progress	326,355	$ 260,932
Deferred Income Taxes	45,105	85,193
Liabilities
Accrued liabilities – other	53,508	66,371
Advance billings on contracts	104,646	73,390
Stockholders' Equity
Retained earnings	1,159,552	$ 1,000,578
Accounting Standards Update 2014-09 \| Calculated under Revenue Guidance in Effect before Topic 606
Assets
Contracts in progress	352,389		420,628
Deferred Income Taxes	46,785		86,740
Liabilities
Accrued liabilities – other	50,435		64,738
Advance billings on contracts	150,081		246,192
Stockholders' Equity
Retained earnings	$ 1,144,904		$ 990,652

Revenue Recognition (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net favorable changes in estimate that resulted in an increase in revenue		$ 23,400
Cumulative effect of contract change, cost of operations		12,300
Decrease in operating income from cumulative effect of contract changes	$ (26,700)	$ (29,200)
Decrease in earnings per share from cumulative effect of contract changes	$ (0.21)	$ (0.23)
Contracts in progress increase		$ 66,000
Revenue recognized from advance billings on contracts		49,000
Revenue from contract with customer	$ 426,853	1,326,766
Difference between Revenue Guidance in Effect before and after Topic 606 \| Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer	$ 17,700	$ 8,500

Revenue Recognition - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018
Contracts with Customers, Asset and Liability [Line Items]
Advance billings on contracts	$ 104,646	$ 73,390
Contracts in Progress
Contracts with Customers, Asset and Liability [Line Items]
Contract with customer, asset	316,341	250,325
Accounts Receivable
Contracts with Customers, Asset and Liability [Line Items]
Contract with customer, asset	102,555	82,801
Other Assets
Contracts with Customers, Asset and Liability [Line Items]
Contract with customer, asset	$ 1,626	$ 1,669

Revenue Recognition - Historical Method (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Assets
Contracts in progress	$ 326,355		$ 326,355			$ 420,628
Deferred Income Taxes	45,105		45,105			86,740
Liabilities
Accrued liabilities – other	53,508		53,508			64,738
Advance billings on contracts	104,646		104,646			246,192
Stockholders' Equity
Retained earnings	1,159,552		1,159,552			990,652
Revenues	425,507	$ 419,360	1,321,891	$ 1,257,600
Cost of operations	326,314	302,267	971,887	883,839
Operating Income	50,395	66,777	201,832	228,477
Provision for Income Taxes	6,482	23,901	43,578	75,556
Net Income	78,077	$ 46,693	205,224	$ 163,898
Accounting Standards Update 2014-09
Assets
Contracts in progress	326,355		326,355		$ 260,932
Deferred Income Taxes	45,105		45,105		85,193
Liabilities
Accrued liabilities – other	53,508		53,508		66,371
Advance billings on contracts	104,646		104,646		73,390
Stockholders' Equity
Retained earnings	1,159,552		1,159,552		$ 1,000,578
Revenues	425,507		1,321,891
Cost of operations	326,314		971,887
Operating Income	50,395		201,832
Provision for Income Taxes	6,482		43,578
Net Income	78,077		205,224
Calculated under Revenue Guidance in Effect before Topic 606 \| Accounting Standards Update 2014-09
Assets
Contracts in progress	352,389		352,389			420,628
Deferred Income Taxes	46,785		46,785			86,740
Liabilities
Accrued liabilities – other	50,435		50,435			64,738
Advance billings on contracts	150,081		150,081			246,192
Stockholders' Equity
Retained earnings	1,144,904		1,144,904			$ 990,652
Revenues	407,759		1,313,392
Cost of operations	315,196		969,683
Operating Income	43,765		195,537
Provision for Income Taxes	4,962		42,005
Net Income	$ 72,967		$ 200,502

Pension Plans and Postretirement Benefits - (Details) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Aug. 31, 2018 USD ($)	Jul. 31, 2018 USD ($) Plan retiree	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Service cost			$ 2,500	$ 1,800	$ 7,700	$ 6,400
Net periodic benefit (income) cost, excluding service costs			(42,400)	(6,900)	(60,100)	(20,800)
Expected future employer contributions, remainder of fiscal year			3,600		3,600
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost			2,380	1,721	7,198	6,017
Transfer of domestic pension benefit obligation to annuity contract		$ 244,100
Number of retirees transferred to annuity contract \| retiree		1,300
Number of domestic pension plans \| Plan		2
Recognized net actuarial gain		$ 35,100	35,130	$ 0	35,130	$ 0
Settlement loss			$ 10,400
Actuarial gain before settlement loss					45,500
Contribution by employer	$ 118,100				$ 157,900

Pension Plans and Postretirement Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jul. 31, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 2,500	$ 1,800	$ 7,700	$ 6,400
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost		2,380	1,721	7,198	6,017
Interest cost		11,575	13,727	36,225	40,735
Expected return on plan assets		(19,272)	(21,019)	(62,450)	(62,659)
Amortization of prior service cost (credit)		565	506	1,665	1,556
Recognized net actuarial gain	$ (35,100)	(35,130)	0	(35,130)	0
Net periodic benefit (income) cost		(39,882)	(5,065)	(52,492)	(14,351)
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost		132	116	459	423
Interest cost		504	557	1,404	1,635
Expected return on plan assets		(548)	(596)	(1,581)	(1,787)
Amortization of prior service cost (credit)		(127)	(79)	(234)	(236)
Recognized net actuarial gain		0	0	0	0
Net periodic benefit (income) cost		$ (39)	$ (2)	$ 48	$ 35

Commitments and Contingencies - Additional Information (Details) - Apollo and Parks Township	3 Months Ended	11 Months Ended	99 Months Ended
	Mar. 31, 2018 claimant lawsuit	Mar. 31, 2016 lawsuit	Mar. 31, 2018 claimant facility
Contingencies And Commitments [Line Items]
Number of lawsuits \| lawsuit	17	17
Number of claimants \| claimant	107		107
Number of facilities \| facility			2

Derivative Financial Instruments - Additional Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net losses on derivative financial instruments in accumulated other comprehensive income	$ 0.3
Notional amount of foreign currency forward contracts	$ 49.0

Derivative Financial Instruments - Summary of Derivative Financial Instruments (Details) - Derivatives Designated as Hedges - FX Forward Contracts - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounts receivable – other
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 218	$ 250
Other Assets
Derivatives, Fair Value [Line Items]
Asset Derivatives	211	348
Accounts payable
Derivatives, Fair Value [Line Items]
Liability Derivatives	120	177
Other Liabilities
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 152	$ 93

Derivative Financial Instruments - Schedule of Effect of Derivative Instruments on Statements of Financial Performance (Details) - Cash Flow Hedges - FX Forward Contracts - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivatives Designated as Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income	$ (63)	$ (349)	$ 12	$ 578
Derivatives Designated as Hedges \| Revenues
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified from accumulated other comprehensive income (loss) into earnings: effective portion	(86)	195	(90)	182
Derivatives Designated as Hedges \| Cost of operations
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified from accumulated other comprehensive income (loss) into earnings: effective portion	119	(470)	147	(179)
Derivatives Not Designated as Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income	$ (1,254)	$ 0	$ 4,743	$ 0

Fair Value Measurements - Summary of Investments and Available-for-Sale Securities Measured at Fair Value (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 11,336
Available-for-sale securities		$ 12,235
Equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	1,851
Available-for-sale securities		2,759
Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	5,170
Available-for-sale securities		4,847
U.S. Government and agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,982
Available-for-sale securities		1,299
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,228
Available-for-sale securities		3,169
Asset-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	105
Available-for-sale securities		161
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	3,461
Available-for-sale securities		2,833
Level 1 \| Equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0
Available-for-sale securities		0
Level 1 \| Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0
Available-for-sale securities		0
Level 1 \| U.S. Government and agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,982
Available-for-sale securities		1,299
Level 1 \| Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,479
Available-for-sale securities		1,534
Level 1 \| Asset-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0
Available-for-sale securities		0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	7,875
Available-for-sale securities		9,402
Level 2 \| Equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	1,851
Available-for-sale securities		2,759
Level 2 \| Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	5,170
Available-for-sale securities		4,847
Level 2 \| U.S. Government and agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0
Available-for-sale securities		0
Level 2 \| Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	749
Available-for-sale securities		1,635
Level 2 \| Asset-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	105
Available-for-sale securities		161
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0
Available-for-sale securities		0
Level 3 \| Equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0
Available-for-sale securities		0
Level 3 \| Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0
Available-for-sale securities		0
Level 3 \| U.S. Government and agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0
Available-for-sale securities		0
Level 3 \| Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0
Available-for-sale securities		0
Level 3 \| Asset-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 0
Available-for-sale securities		$ 0

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
FX Forward Contracts
Fair Values Of Financial Instruments [Line Items]
Fair value of foreign currency forward contracts	$ 0.2	$ 0.3

Stock-Based Compensation - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock based compensation expense	$ 2.8	$ 3.9	$ 9.1	$ 12.6
Stock-based compensation, tax benefits	$ 0.5	$ 1.4	$ 1.7	$ 4.4

Segment Reporting - Additional Information (Details)	9 Months Ended
Segment Reporting - Additional Information (Details)	Sep. 30, 2018 segment
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Number of reportable segments	3

Segment Reporting - Schedule of Operating Results by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting, Other Significant Reconciling Item [Line Items]
Revenues	$ 425,507	$ 419,360	$ 1,321,891	$ 1,257,600
Operating Income	50,395	66,777	201,832	228,477
Interest income	1,121	402	2,340	750
Interest expense	(7,925)	(3,837)	(19,354)	(11,260)
Other – net	40,968	7,252	63,984	21,487
Total Other Income (Expense)	34,164	3,817	46,970	10,977
Income before Provision for Income Taxes	84,559	70,594	248,802	239,454
Operating Segments
Segment Reporting, Other Significant Reconciling Item [Line Items]
Operating Income	55,995	73,406	216,560	242,237
Operating Segments \| Nuclear Operations Group
Segment Reporting, Other Significant Reconciling Item [Line Items]
Revenues	319,325	324,545	968,096	962,492
Operating Income	45,580	66,459	180,283	203,503
Operating Segments \| Nuclear Services Group
Segment Reporting, Other Significant Reconciling Item [Line Items]
Revenues	28,366	27,507	90,995	100,146
Operating Income	6,494	776	11,182	16,577
Operating Segments \| Nuclear Power Group
Segment Reporting, Other Significant Reconciling Item [Line Items]
Revenues	79,162	68,621	267,675	200,864
Operating Income	9,063	8,426	38,637	27,094
Operating Segments \| Other
Segment Reporting, Other Significant Reconciling Item [Line Items]
Operating Income	(5,142)	(2,255)	(13,542)	(4,937)
Adjustments and Eliminations
Segment Reporting, Other Significant Reconciling Item [Line Items]
Revenues	(1,346)	(1,313)	(4,875)	(5,902)
Adjustments and Eliminations \| Nuclear Operations Group
Segment Reporting, Other Significant Reconciling Item [Line Items]
Revenues	(978)	(192)	(2,958)	(592)
Adjustments and Eliminations \| Nuclear Services Group
Segment Reporting, Other Significant Reconciling Item [Line Items]
Revenues	(273)	(1,043)	(1,813)	(5,113)
Adjustments and Eliminations \| Nuclear Power Group
Segment Reporting, Other Significant Reconciling Item [Line Items]
Revenues	(95)	(78)	(104)	(197)
Unallocated Corporate
Segment Reporting, Other Significant Reconciling Item [Line Items]
Operating Income	$ (5,600)	$ (6,629)	$ (14,728)	$ (13,760)

Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Basic:
Net Income Attributable to BWX Technologies, Inc.	$ 77,919	$ 46,553	$ 205,023	$ 163,534
Weighted-average common shares (in shares)	99,421,031	99,328,677	99,542,933	99,313,264
Basic earnings per common share (in usd per share)	$ 0.78	$ 0.47	$ 2.06	$ 1.65
Diluted:
Net Income Attributable to BWX Technologies, Inc.	$ 77,919	$ 46,553	$ 205,023	$ 163,534
Weighted-average common shares (in shares)	99,421,031	99,328,677	99,542,933	99,313,264
Effect of dilutive securities:
Stock options, restricted stock units and performance shares (in shares)	999,735	931,578	958,664	1,054,119
Adjusted weighted-average common shares (in shares)	100,420,766	100,260,255	100,501,597	100,367,383
Diluted earnings per common share (in usd per share)	$ 0.78	$ 0.46	$ 2.04	$ 1.63
Number of shares that would be antidilutive (in shares)			0	0

Revenue Recognition - Remaining Performance Obligations (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, expected timing of satisfaction, period	9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	$ 406
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	$ 1,068
Remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	$ 2,360
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	3,834
Nuclear Operations Group \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	304
Nuclear Operations Group \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	889
Nuclear Operations Group \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	1,747
Nuclear Operations Group \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	2,940
Nuclear Services Group \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	18
Nuclear Services Group \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	3
Nuclear Services Group \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	5
Nuclear Services Group \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	26
Nuclear Power Group \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	84
Nuclear Power Group \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	176
Nuclear Power Group \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	608
Nuclear Power Group \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total Remaining Performance Obligations	$ 868