Operating Segments and Related Information (Details 3) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets (accounts receivable, net and inventories)	$ 689,827	$ 719,190
Surveillance
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets (accounts receivable, net and inventories)	275,705	285,602
Instruments
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets (accounts receivable, net and inventories)	110,048	130,363
OEM & Emerging Markets
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets (accounts receivable, net and inventories)	118,408	93,925
Maritime
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets (accounts receivable, net and inventories)	62,290	73,506
Detection
Segment Reporting, Asset Reconciling Item [Line Items]
Segment assets (accounts receivable, net and inventories)	$ 29,730	$ 30,057