Segment Information - Disaggregation of Revenue By Geographical Region (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Revenues, net	$ 176,244	$ 165,625	$ 520,172	$ 540,632
Domestic
Segment Reporting Information [Line Items]
Revenues, net	171,986	161,858	510,228	529,598
Foreign
Segment Reporting Information [Line Items]
Revenues, net	$ 4,258	$ 3,767	$ 9,944	$ 11,034
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	97.60%	97.70%	98.10%	98.00%
Geographic Concentration Risk | Net Revenue | Foreign
Segment Reporting Information [Line Items]
Concentration risk percentage	2.40%	2.30%	1.90%	2.00%