| Cover | Feb. 24, 2025 | Feb. 27, 2024 |
| Document Information [Line Items] | ||
| Document Type | 8-K | |
| Document Period End Date | Feb. 24, 2025 | |
| Entity Registrant Name | BWX TECHNOLOGIES, INC. | |
| Entity Incorporation, State or Country Code | DE | |
| Entity File Number | 001-34658 | |
| Entity Tax Identification Number | 80-0558025 | |
| Entity Address, Address Line One | 800 Main Street, 4th Floor | |
| Entity Address, Postal Zip Code | 24504 | |
| Entity Address, State or Province | VA | |
| Entity Address, City or Town | Lynchburg, | |
| City Area Code | 980 | |
| Local Phone Number | 365-4300 | |
| Written Communications | false | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Title of 12(b) Security | Common Stock, $0.01 par value | |
| Trading Symbol | BWXT | |
| Security Exchange Name | NYSE | |
| Entity Emerging Growth Company | false | |
| Amendment Flag | false | |
| Entity Central Index Key | 0001486957 |
