Business Combinations - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended					12 Months Ended
	Dec. 31, 2016	Aug. 31, 2016	Jul. 31, 2016	Mar. 31, 2015	Feb. 28, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Payment to acquire business, paid with cash on hand						$ 27,708	$ 12,066	$ 1,150
Contingent consideration earned						774	$ 0	$ 0
Acquisition and integration costs	$ 1,000					1,000
ARAS
Business Acquisition [Line Items]
Payment to acquire business, paid with cash on hand					$ 7,640
Contingent consideration to be earned					$ 4,000
Contingent consideration earn-out period					2 years
Kubit
Business Acquisition [Line Items]
Payment to acquire business, paid with cash on hand				$ 4,426
Contingent consideration to be earned				$ 3,300
Contingent consideration earn-out period				3 years
Contingent consideration earned						$ 400
BuildIT
Business Acquisition [Line Items]
Payment to acquire business, paid with cash on hand			$ 3,910
LPT
Business Acquisition [Line Items]
Payment to acquire business, paid with cash on hand		$ 17,211
MWF
Business Acquisition [Line Items]
Payment to acquire business, paid with cash on hand	$ 6,587