Accounts Payable and Accrued Expenses - Summary of Current Portion of Earn-out Liabilities and Long term Portion of Earn-out Liability (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Business Acquisition Contingent Consideration [Line Items]
Balance of earn-out at beginning of period	$ 24,214	$ 32,671
Fair value adjustment	3,897	347
Compensation expense adjustment	290	302
Foreign currency translation adjustment	200	288
Payment	(2,155)	(1,100)
Total earn-out liability at end of period	26,446	32,508
Less: current portion of earn-out	(13,062)	(22,565)	$ (13,527)
Balance of long term portion of earn-out recorded in other liabilities at end of period	13,384	9,943
Energy Segment [Member]
Business Acquisition Contingent Consideration [Line Items]
Balance of earn-out at beginning of period	24,214	29,304
Fair value adjustment	3,897	847
Compensation expense adjustment	290	302
Foreign currency translation adjustment	200	288
Payment	(2,155)
Total earn-out liability at end of period	26,446	30,741
Less: current portion of earn-out	(13,062)	(21,898)
Balance of long term portion of earn-out recorded in other liabilities at end of period	$ 13,384	8,843
Environmental Segment [Member]
Business Acquisition Contingent Consideration [Line Items]
Balance of earn-out at beginning of period		3,367
Fair value adjustment		(500)
Payment		(1,100)
Total earn-out liability at end of period		1,767
Less: current portion of earn-out		(667)
Balance of long term portion of earn-out recorded in other liabilities at end of period		$ 1,100