Condensed Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenues	$ 457,463	$ 428,229
Costs and Expenses:
Cost of operations	327,364	303,216
Research and development costs	3,607	1,519
Gains on asset disposals and impairments, net	(8)	0
Selling, general and administrative expenses	53,762	51,097
Total Costs and Expenses	384,725	355,832
Equity in Income of Investees	7,150	3,875
Operating Income	79,888	76,272
Other Income (Expense):
Interest income	778	137
Interest expense	(3,560)	(3,517)
Other – net	7,910	7,486
Total Other Income (Expense)	5,128	4,106
Income before Provision for Income Taxes	85,016	80,378
Provision for Income Taxes	18,603	24,592
Net Income	66,413	55,786
Net (Income) Loss Attributable to Noncontrolling Interest	28	(67)
Net Income Attributable to BWX Technologies, Inc.	$ 66,441	$ 55,719
Basic:
Net Income Attributable to BWX Technologies, Inc. (in usd per share)	$ 0.67	$ 0.56
Diluted:
Net Income Attributable to BWX Technologies, Inc. (in usd per share)	$ 0.66	$ 0.55
Shares used in the computation of earnings per share (Note 9):
Basic (in shares)	99,526,187	99,444,910
Diluted (in shares)	100,512,287	100,690,968