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	6 Months Ended
	Jun. 30, 2017	Jun. 30, 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	(1,755)	1,033
Compensation expense adjustment	597	610
Foreign currency translation adjustment	523	(529)
Settlement through an exchange of accounts receivable		(3,190)
Payment	(15,193)	(2,341)
Total earn-out liability at end of period	8,386	28,254
Less: current portion of earn-out	(6,970)	(18,247)	$ (13,527)
Balance of long term portion of earn-out recorded in other liabilities at end of period	1,416	10,007
Energy Segment [Member]
Business Acquisition Contingent Consideration [Line Items]
Balance of earn-out at beginning of period	24,214	29,304
Fair value adjustment	(1,755)	1,533
Compensation expense adjustment	597	610
Foreign currency translation adjustment	523	(529)
Settlement through an exchange of accounts receivable		(3,190)
Payment	(15,193)	(1,241)
Total earn-out liability at end of period	8,386	26,487
Less: current portion of earn-out	(6,970)	(17,580)
Balance of long term portion of earn-out recorded in other liabilities at end of period	$ 1,416	8,907
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