Segment Information - Disaggregation of Revenue By Geographical Region (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Revenues, net	$ 178,057	$ 190,944	$ 343,928	$ 375,007
Domestic
Segment Reporting Information [Line Items]
Revenues, net	174,109	186,726	338,243	367,740
Foreign
Segment Reporting Information [Line Items]
Revenues, net	$ 3,948	$ 4,218	$ 5,685	$ 7,267
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%	97.80%	98.30%	98.10%
Geographic Concentration Risk | Net Revenue | Foreign
Segment Reporting Information [Line Items]
Concentration risk percentage	2.20%	2.20%	1.70%	1.90%