Segment Information - Disaggregation of Revenue By Geographical Region (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Revenues, net	$ 165,625	$ 202,428	$ 540,632	$ 654,988
Domestic
Segment Reporting Information [Line Items]
Revenues, net	161,858	196,069	529,598	635,086
Foreign
Segment Reporting Information [Line Items]
Revenues, net	$ 3,767	$ 6,359	$ 11,034	$ 19,902
Geographic Concentration Risk | Net Revenue
Segment Reporting Information [Line Items]
Concentration risk percentage	100.00%	100.00%	100.00%	100.00%
Geographic Concentration Risk | Net Revenue | Domestic
Segment Reporting Information [Line Items]
Concentration risk percentage	97.70%	96.90%	98.00%	97.00%
Geographic Concentration Risk | Net Revenue | Foreign
Segment Reporting Information [Line Items]
Concentration risk percentage	2.30%	3.10%	2.00%	3.00%