Property, Plant and Equipment, Net - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Property, Plant and Equipment, Net
Property, plant and equipment, net	$ 328,909,000		$ 328,909,000		$ 313,418,000
Impairment of property and equipment			0	$ 0
Depreciation expense	7,000,000	$ 5,800,000	14,100,000	$ 11,200,000
Foreign
Property, Plant and Equipment, Net
Property, plant and equipment, net	86,000,000		86,000,000		82,800,000
Construction in progress
Property, Plant and Equipment, Net
Property, plant and equipment, net	$ 116,246,000		$ 116,246,000		$ 117,173,000