Goodwill - Changes in Goodwill by Reporting Units (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Beginning Balance	$ 46,744	$ 26,371
Additions	2,412	20,629
Foreign Currency Translation	3,594	(256)
Ending Balance	52,750	46,744
Factory Metrology
Goodwill [Roll Forward]
Beginning Balance	37,861	21,360
Additions	2,357	16,709
Foreign Currency Translation	2,941	(208)
Ending Balance	43,159	37,861
Construction BIM-CIM
Goodwill [Roll Forward]
Beginning Balance	6,078	3,429
Additions	0	2,682
Foreign Currency Translation	443	(33)
Ending Balance	6,521	6,078
Public Safety Forensics
Goodwill [Roll Forward]
Beginning Balance	2,805	1,582
Additions	55	1,238
Foreign Currency Translation	210	(15)
Ending Balance	$ 3,070	$ 2,805