Accounts Payable and Accrued Expenses - Summary of Current Portion of Earnout Liabilities and Long term Portion of Earnout Liability (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Business Acquisition Contingent Consideration [Line Items]
Fair value adjustment		$ (1,755)
Less: current portion of earnout	$ (1,198)		$ (2,989)
Energy Solutions Segment [Member]
Business Acquisition Contingent Consideration [Line Items]
Earnout accrued at beginning of period	4,475	24,214
Fair value adjustment		(1,755)
Compensation expense adjustment	222	597
Payment	(2,050)	(15,193)
Foreign currency translation adjustment		523
Total earnout liability at end of period	2,647	8,386
Less: current portion of earnout	(1,198)	(6,970)
Balance of long term portion of earnout recorded in other liabilities at end of period	$ 1,449	$ 1,416