Condensed Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenues	$ 519,878	$ 506,000	$ 1,566,606	$ 1,393,685
Costs and Expenses:
Cost of operations	373,783	357,732	1,133,760	999,390
Research and development costs	2,933	5,125	11,565	15,631
Losses (gains) on asset disposals and impairments, net	25	(6)	324	145
Selling, general and administrative expenses	62,638	52,561	170,733	158,296
Total Costs and Expenses	439,379	415,412	1,316,382	1,173,462
Equity in Income of Investees	8,271	7,874	19,247	22,418
Operating Income	88,770	98,462	269,471	242,641
Other Income (Expense):
Interest income	161	232	453	784
Interest expense	(7,701)	(8,858)	(23,533)	(27,103)
Other – net	10,652	4,670	28,019	18,795
Total Other Income (Expense)	3,112	(3,956)	4,939	(7,524)
Income before Provision for Income Taxes	91,882	94,506	274,410	235,117
Provision for Income Taxes	18,687	19,508	61,199	52,009
Net Income	73,195	74,998	213,211	183,108
Net Income Attributable to Noncontrolling Interest	(24)	(188)	(283)	(442)
Net Income Attributable to BWX Technologies, Inc.	$ 73,171	$ 74,810	$ 212,928	$ 182,666
Basic:
Net Income Attributable to BWX Technologies, Inc. (in usd per share)	$ 0.77	$ 0.78	$ 2.23	$ 1.92
Diluted:
Net Income Attributable to BWX Technologies, Inc. (in usd per share)	$ 0.76	$ 0.78	$ 2.22	$ 1.91
Shares used in the computation of earnings per share (Note 10):
Basic (in shares)	95,483,003	95,420,626	95,450,994	95,344,349
Diluted (in shares)	95,730,696	95,811,198	95,706,880	95,769,919