Debt - Long-Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Less - unamortized original issue discount	$ (6,543)	$ (10,053)
Total debt, net of unamortized discounts	352,832	356,822
Current portion of long-term debt, net of unamortized discounts	(13,125)	(10,313)
Long-term debt, net of unamortized discounts	339,707	346,509
2018 Credit Agreement | 2018 Term Loan
Debt Instrument [Line Items]
Total long-term debt, gross	129,375	136,875
Less – deferred financing costs	(1,294)	(1,715)
Total debt, net of unamortized discounts	128,081	135,160
Senior Convertible Notes 2016
Debt Instrument [Line Items]
Total long-term debt, gross	230,000	230,000
Less - unamortized original issue discount	(3,783)	(6,004)
Less – deferred financing costs	(1,466)	(2,334)
Total debt, net of unamortized discounts	$ 224,751	$ 221,662