Operating Segments and Related Information (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Business Unit Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 481,998	$ 452,707	$ 926,734	$ 892,325
Intersegment revenue	0	0	0	0
Earnings from operations	63,737	88,666	144,819	144,158
Government and Defense
Business Unit Reporting, Revenue Reconciling Item [Line Items]
Revenue	197,509	161,027	370,859	320,358
Intersegment revenue	(1,436)	(4,573)	(2,947)	(6,101)
Earnings from operations	48,970	45,548	97,237	91,730
Industrial
Business Unit Reporting, Revenue Reconciling Item [Line Items]
Revenue	188,902	188,421	368,272	359,079
Intersegment revenue	(3,348)	(6,164)	(9,546)	(12,496)
Earnings from operations	62,077	58,096	118,974	103,550
Commercial
Business Unit Reporting, Revenue Reconciling Item [Line Items]
Revenue	95,587	103,259	187,603	212,888
Intersegment revenue	(5,784)	(3,601)	(10,217)	(8,081)
Earnings from operations	12,980	17,367	25,928	31,839
Eliminations
Business Unit Reporting, Revenue Reconciling Item [Line Items]
Intersegment revenue	(10,568)	(14,338)	(22,710)	(26,678)
Total Segments [Member]
Business Unit Reporting, Revenue Reconciling Item [Line Items]
Revenue	481,998	452,707	926,734	892,325
Earnings from operations	$ 124,027	$ 121,011	$ 242,139	$ 227,119