Business Combinations - Schedule of Purchase Price Allocations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Mar. 31, 2017
Purchase price allocation
Goodwill	$ 98,086	$ 98,086
Series of Individually Immaterial Business Acquisitions
Purchase price allocation
Cash and cash equivalents excluding restricted cash	2,963
Restricted cash	3
Accounts receivable	6,400
Property and equipment, net	29,896
Goodwill	5,541
Intangibles	7,082
Other assets	2,051
Inventories	528
Total assets acquired	54,464
Accounts payable and other current liabilities	(11,180)
Deferred tax liability	(2,819)
Other liabilities	(3)
Long-term debt	(20,813)
Noncontrolling interest	(815)
Total liabilities assumed	(35,630)
Enterprise value	18,834
Less fair value of noncontrolling interest	3,889
Total net assets acquired	14,945
DBMG | PDC Operations (Australia) Pty Ltd (PDC) and BDS VirCon (BDS)
Purchase price allocation
Cash and cash equivalents		621
Accounts receivable		5,558
Costs and recognized earnings in excess of billings on uncompleted contracts		1,686
Property and equipment, net		8,043
Goodwill		11,827
Intangibles		3,955
Other assets		1,209
Total assets acquired		32,899
Accounts payable and other current liabilities		(5,924)
Billings in excess of costs and recognized earnings on uncompleted contracts		(617)
Deferred tax liability		(169)
Other liabilities		(685)
Total liabilities assumed		(7,395)
Total net assets acquired		$ 25,504
Energy
Purchase price allocation
Accounts receivable	1,303
Property and equipment, net	42,758
Goodwill	1,257
Intangibles	4,984
Other assets	79
Total assets acquired	50,381
Accounts payable and other current liabilities	(898)
Deferred tax liability	(7,086)
Total liabilities assumed	(7,984)
Bargain purchase gain	(340)
Enterprise value	$ 42,057