Operating Segments and Related Information (Details 3) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets (accounts receivable, net and inventories)	$ 697,400	$ 719,190
Surveillance
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets (accounts receivable, net and inventories)	257,612	286,058
Instruments
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets (accounts receivable, net and inventories)	109,601	130,135
OEM & Emerging Markets
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets (accounts receivable, net and inventories)	113,830	93,925
Maritime
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets (accounts receivable, net and inventories)	87,414	73,506
Detection
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets (accounts receivable, net and inventories)	$ 36,385	$ 30,057