Business Acquisitions and Divestitures - Pro Forma Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
C&CA
Business Acquisition, Pro Forma Information [Abstract]
Unaudited pro forma revenue	$ 162,459	$ 155,626
Unaudited pro forma net (loss) income from continuing operations	$ 3,886	5,365
Lavante
Business Acquisition, Pro Forma Information [Abstract]
Unaudited pro forma revenue		143,198	$ 140,994
Unaudited pro forma net (loss) income from continuing operations		$ (3,418)	$ (5,516)