Segment Information - Disaggregation of Revenue By Geographical Region (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Revenues, net	$ 190,944	$ 199,140	$ 375,007	$ 452,560
Domestic
Segment Reporting Information [Line Items]
Revenues, net	186,726	193,314	367,740	439,018
Foreign
Segment Reporting Information [Line Items]
Revenues, net	$ 4,218	$ 5,826	$ 7,267	$ 13,542
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	97.80%	97.10%	98.10%	97.00%
Geographic Concentration Risk | Net Revenue | Foreign
Segment Reporting Information [Line Items]
Concentration risk percentage	2.20%	2.90%	1.90%	3.00%