Operating Segments and Related Information (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue - External Customers	$ 381,928	$ 375,366	$ 1,119,420	$ 1,096,288
Intersegment revenue	0	0	0	0
Earnings (loss) from operations	75,982	70,009	212,267	171,824
Surveillance
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue - External Customers	131,598	125,343	352,312	362,073
Intersegment revenue	2,653	2,659	8,400	6,642
Earnings (loss) from operations	39,918	33,393	96,464	79,293
Instruments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue - External Customers	74,796	82,561	248,877	250,583
Intersegment revenue	777	74	2,687	548
Earnings (loss) from operations	21,555	23,191	77,959	64,678
OEM & Emerging Markets
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue - External Customers	51,448	49,888	137,568	148,927
Intersegment revenue	8,020	4,721	25,778	15,277
Earnings (loss) from operations	14,233	12,798	33,507	35,518
Maritime
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue - External Customers	38,920	44,728	141,922	152,533
Intersegment revenue	85	804	1,667	2,308
Earnings (loss) from operations	1,848	4,614	13,058	23,159
Security
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue - External Customers	59,331	48,648	158,185	122,692
Intersegment revenue	2,386	2,971	10,393	7,361
Earnings (loss) from operations	7,222	6,988	18,911	14,560
Detection
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue - External Customers	25,835	24,198	80,556	59,480
Intersegment revenue	0	4	0	64
Earnings (loss) from operations	5,290	4,167	17,349	5,519
Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Intersegment revenue	(13,921)	(11,233)	(48,925)	(32,200)
Earnings (loss) from operations	$ (14,084)	$ (15,142)	$ (44,981)	$ (50,903)