Operating Segments and Related Information (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 434,124	$ 402,729	$ 840,938	$ 782,201
Intersegment revenue	0	0	0	0
Earnings from operations	66,630	65,212	125,716	122,589
Surveillance
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	129,209	113,440	247,938	237,591
Intersegment revenue	(3,331)	(4,755)	(8,087)	(8,979)
Earnings from operations	33,007	26,595	59,372	62,460
Instruments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	85,969	78,068	163,824	157,487
Intersegment revenue	(7,325)	(1,213)	(13,114)	(2,788)
Earnings from operations	23,627	19,695	44,773	39,676
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	49,709	63,380	94,786	110,441
Intersegment revenue	(3,640)	(3,836)	(6,765)	(6,308)
Earnings from operations	1,288	4,410	1,603	2,241
OEM & Emerging Markets
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	87,447	56,980	172,212	104,825
Intersegment revenue	(9,361)	(8,833)	(18,530)	(17,010)
Earnings from operations	26,340	16,757	50,697	27,443
Maritime
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	55,102	55,163	103,653	106,883
Intersegment revenue	(621)	(1,458)	(1,298)	(2,072)
Earnings from operations	9,390	7,521	14,594	13,328
Detection
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	26,688	35,698	58,525	64,974
Intersegment revenue	(1)	(31)	(1)	(31)
Earnings from operations	7,024	10,320	15,761	18,557
Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Intersegment revenue	(24,279)	(20,126)	(47,795)	(37,188)
Total Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Earnings from operations	$ 100,676	$ 85,298	$ 186,800	$ 163,705