Property and Equipment, net - Schedule of Property and Equipment, net (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 109,504	$ 91,731
Less: Accumulated depreciation and amortization	(74,611)	(55,329)
Total property and equipment, net	34,893	36,402
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	6,888	4,126
Leasehold improvements, furniture, and computer hardware
Property, Plant and Equipment [Line Items]
Total property and equipment	14,755	13,709
Vehicles
Property, Plant and Equipment [Line Items]
Total property and equipment	55,093	43,413
Computer software
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 32,768	$ 30,483