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Arrangement Duration Trading Arrangement Duration Exercises of stock options Stock Issued During Period, Value, Stock Options Exercised Costs and Expenses: Costs and Expenses [Abstract] Restricted cash and cash equivalents Restricted Cash and Cash Equivalents, Current Government Operations Government Operations Segment [Member] Government Operations Segment Unrealized gains (losses) arising during the period, net of tax (provision) benefit of $(178) and $132, respectively Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Provision for Income Taxes Income Tax, Policy [Policy Text Block] Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Total Available-For-Sale Debt Securities And Equity Securities, FV-NI Available-For-Sale Debt Securities And Equity Securities, FV-NI Segments [Domain] Segments [Domain] Accumulated Postretirement Benefit Obligation Liability, Other Postretirement Defined Benefit Plan, Noncurrent 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Financial Instrument [Axis] Financial Instrument [Axis] Segment Reporting Segment Reporting Disclosure [Text Block] Current portion of long-term debt Long-Term Debt, Current Maturities Adjustments to reconcile net income to net cash provided by operating activities: Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Government Government Customers [Member] Government Customers [Member] Entity Shell Company Entity Shell Company Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Title Trading Arrangement, Individual Title Nuclear Manufacturing Nuclear Manufacturing [Member] Nuclear Manufacturing [Member] Statement [Table] Statement [Table] Recognition of losses for pension and postretirement plans Recognition Of Gains Losses For Pension And Postretirement Plans Recognition of gains losses for pension and postretirement plans. Measurement Frequency [Domain] Measurement Frequency [Domain] Comprehensive Loss (Income) Attributable to Noncontrolling Interest Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Diluted: Net Income (Loss) Available to Common Stockholders, Diluted [Abstract] Consolidation Items [Domain] Consolidation Items [Domain] City Area Code City Area Code Current Liabilities: Liabilities, Current [Abstract] Interest Interest Paid, Excluding Capitalized Interest, Operating Activities Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Level 1 Fair Value, Inputs, Level 1 [Member] Currency translation adjustments Currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Total Current Assets Assets, Current Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Senior Notes Senior Notes [Member] SCHEDULE OF NON-CASH INVESTING ACTIVITY: Noncash Investing and Financing Items [Abstract] U.S. Government U.S. Government [Member] U.S. Government Repurchases of common stock Payments for Repurchase of Common Stock Long-Term Debt Long-Term Debt, Excluding Current Maturities Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Revenue, remaining performance obligation, percentage Revenue, Remaining Performance Obligation, Percentage Kinectrics Holdings, Inc. Kinectrics Holdings, Inc. [Member] Kinectrics Holdings, Inc. Aerojet Ordnance Tennessee, Inc. Aerojet Ordnance Tennessee, Inc. [Member] Aerojet Ordnance Tennessee, Inc. Earnings per Common Share: Earnings Per Share [Abstract] Revenue from External Customers by Products and Services Revenue from External Customers by Products and Services [Table Text Block] Retained earnings Retained Earnings (Accumulated Deficit) Schedule of Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Revenue from Contract with Customer Benchmark Revenue from Contract with Customer Benchmark [Member] Senior Notes Due 2028 Senior Notes Due 2028 [Member] Senior Notes Due 2028 Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Equity Awards Adjustments Equity Awards Adjustments [Member] NET CASH PROVIDED BY (USED IN) FINANCING ACTIVITIES Net Cash Provided by (Used in) Financing Activities Underlying Securities Award Underlying Securities Amount Amendment Flag Amendment Flag Fair value of senior notes Long-Term Debt, Fair Value Entity Registrant Name Entity Registrant Name Acquisition of business Payments to Acquire Businesses, Gross Point-in-time Transferred at Point in Time [Member] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Depreciation and amortization Depreciation, Depletion and Amortization Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Cash Held for Decommissioning of Facilities Cash Held For Decommissioning Of Facilities [Member] Cash held for decommissioning of facilities. Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Restricted Cash and Cash Equivalents Restrictions on Cash and Cash Equivalents [Table Text Block] Machinery and equipment Machinery and Equipment [Member] Fair Value as of Grant Date Award Grant Date Fair Value Customer Concentration Risk Customer Concentration Risk [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Stockholders' Equity: Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Geographical [Domain] Geographical [Domain] Customer relationships Customer-Related Intangible Assets [Member] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Operating Income Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Modification of Contract Schedule of Disaggregated Revenues Disaggregation of Revenue [Table Text Block] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Consolidation Consolidation, Policy [Policy Text Block] Advance billings on contracts Billings In Excess Of Cost1 Billings In Excess Of Cost1 Restatement Determination Date: Restatement Determination Date [Axis] Title of 12(b) Security Title of 12(b) Security Concentration Risk Type [Axis] Concentration Risk Type [Axis] Common stock, par value $0.01 per share, authorized 325,000,000 shares; issued 128,644,088 and 128,320,295 shares at March 31, 2025 and December 31, 2024, respectively Common Stock, Value, Issued Net gains on derivative financial instruments Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] Retainages Accounts Receivable, Retainage Accounts Receivable, Retainage Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Other, net Payments for (Proceeds from) Other Investing Activities Contracts in progress Cost in Excess Of Billings, Current1 Cost in Excess Of Billings, Current1 Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Preferred stock, par value $0.01 per share, authorized 75,000,000 shares; No shares issued Preferred Stock, Value, Issued Sales and maturities of securities Proceeds from Sale, Maturity and Collection of Investments Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Net Income Attributable to BWX Technologies, Inc. (in usd per share) Basic earnings per common share (in usd per share) Earnings Per Share, Basic Accounts payable Increase (Decrease) in Accounts Payable Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Accrued capital expenditures included in accounts payable Capital Expenditures Incurred but Not yet Paid Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Net Income Attributable to BWX Technologies, Inc. Net Income (Loss) Available to Common Stockholders, Basic Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Total Current Liabilities Liabilities, Current Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Shares used in the computation of earnings per share (Note 9): Weighted Average Number of Shares Outstanding, Diluted [Abstract] TOTAL ASSETS Assets Cost of operations Cost of operations Cost of Goods and Services Sold Tax (benefit) provision on reclassification adjustment for losses (gains) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax Purchases of property, plant and equipment Payments to Acquire Property, Plant, and Equipment Other Liabilities Other Liabilities, Noncurrent Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Commitments and Contingencies (Note 5) Commitments and Contingencies Reclassification adjustment for gains included in net income, net of tax provision of $80 and $—, respectively Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Termination Date Trading Arrangement Termination Date Pension liabilities, accrued postretirement benefit obligations and employee benefits Increase Decrease In Pension Postretirement And Accrued Employee Benefits The increase (decrease) during the reporting period in the amount due to fund pension and non-pension benefits to employees, retired and disabled former employees, as well as the increase (decrease) during the period of accrued employee benefits. Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Stock-Based Compensation Share-Based Payment Arrangement [Text Block] Entity Address, City or Town Entity Address, City or Town Borrowings of long-term debt Proceeds from Issuance of Long-Term Debt Debt Instrument [Axis] Debt Instrument [Axis] Stock based compensation expense Share-Based Payment Arrangement, Expense Net Income Attributable to BWX Technologies, Inc. Net Income (Loss) Attributable to Parent Net Income (Loss) Attributable to Parent Trading Arrangement: Trading Arrangement [Axis] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Business Acquisition [Axis] Business Acquisition [Axis] Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Entity File Number Entity File Number Derivative financial instruments Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Revenue Recognition Revenue from Contract with Customer [Text Block] Document Fiscal Year Focus Document Fiscal Year Focus Segment Reporting, Revenue from External Customer, Product and Service [Table] Segment Reporting, Revenue from External Customer, Product and Service [Table] Noncontrolling Interest Noncontrolling Interest [Member] Income Statement [Abstract] Income Statement [Abstract] Entity Address, Address Line One Entity Address, Address Line One Shares placed in treasury Treasury Stock, Value, Acquired, Cost Method Revenues from External Customers [Line Items] Revenue from External Customer [Line Items] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] EFFECTS OF EXCHANGE RATE CHANGES ON CASH Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations Accrued liabilities – other Other Accrued Liabilities, Current Name Forgone Recovery, Individual Name Document Period End Date Document Period End Date Contract with Customer, Basis of Pricing [Domain] Contract with Customer, Basis of Pricing [Domain] Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Senior Notes Due 2029 Senior Notes Due 2029 [Member] Senior Notes Due 2029 Income of investees, net of dividends Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Insider Trading Arrangements [Line Items] Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Revenue recognized from advance billings on contracts Contract with Customer, Liability, Revenue Recognized Adjustment to Compensation: Adjustment to Compensation [Axis] Retainages Accounts Receivable [Member] Net Income Attributable to Noncontrolling Interest Net Income (Loss) Attributable to Noncontrolling Interest FX Forward Contracts Foreign Exchange Contract [Member] Restricted cash and cash equivalents included in Other Assets Restricted Cash and Cash Equivalents, Noncurrent Document Transition Report Document Transition Report Document Quarterly Report Document Quarterly Report Reclassification adjustment for gains included in net income, net of tax provision of $37 and $21, respectively Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Customer [Domain] Customer [Domain] Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Current Reporting Status Entity Current Reporting Status Retained Earnings Retained Earnings [Member] Restricted cash and cash equivalents Restricted Cash and Cash Equivalents Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Basic (in shares) Weighted-average common shares (in shares) Weighted Average Number of Shares Outstanding, Basic Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Tax provision on unrealized gains on investments OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax Schedule of Revenues from External Customerss [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Total Stockholders' Equity Beginning balance Ending balance Accumulated other comprehensive income (loss) Equity, Including Portion Attributable to Noncontrolling Interest Property, plant, and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Executive Category: Executive Category [Axis] Two Utility Customers Two Utility Customers [Member] Two Utility Customers Name Awards Close in Time to MNPI Disclosures, Individual Name Commercial Operations Commercial Operations Segment [Member] Commercial Operations Segment Entity Filer Category Entity Filer Category Time-and-Materials Time-and-Materials Contract [Member] Revenue, remaining performance obligation, amount Revenue, Remaining Performance Obligation, Amount Company Selected Measure Name Company Selected Measure Name