Operating Segments and Related Information (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Business Unit Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 471,248	$ 434,898	$ 1,397,982	$ 1,327,223
Intersegment revenue	0	0	0	0
Earnings from operations	74,388	88,552	219,207	232,710
Government and Defense
Business Unit Reporting, Revenue Reconciling Item [Line Items]
Revenue	213,348	171,955	584,207	492,313
Intersegment revenue	(959)	(2,327)	(3,906)	(8,428)
Earnings from operations	56,298	53,878	153,535	145,608
Industrial
Business Unit Reporting, Revenue Reconciling Item [Line Items]
Revenue	176,617	177,151	544,889	536,231
Intersegment revenue	(3,818)	(3,455)	(13,364)	(15,950)
Earnings from operations	58,344	56,046	177,318	159,597
Commercial
Business Unit Reporting, Revenue Reconciling Item [Line Items]
Revenue	81,283	85,792	268,886	298,679
Intersegment revenue	(4,355)	(5,845)	(14,572)	(13,926)
Earnings from operations	7,569	10,441	33,497	42,280
Eliminations
Business Unit Reporting, Revenue Reconciling Item [Line Items]
Intersegment revenue	(9,132)	(11,627)	(31,842)	(38,304)
Total Segments [Member]
Business Unit Reporting, Revenue Reconciling Item [Line Items]
Revenue	471,248	434,898	1,397,982	1,327,223
Earnings from operations	$ 122,211	$ 120,365	$ 364,350	$ 347,485