Debt - Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Mar. 05, 2018
Debt Instrument [Line Items]
Total long-term debt, gross	$ 356,562
Less – unamortized original issue discount	(5,346)	$ (10,053)
Less – deferred financing costs			$ (2,800)
Total debt, net of unamortized discounts	351,217	356,822
Current portion of long-term debt, net of unamortized discounts	(14,063)	(10,313)
Long-term debt, net of unamortized discounts	337,154	346,509
2018 Credit Agreement
Debt Instrument [Line Items]
Less – deferred financing costs	(1,200)
2018 Credit Agreement | 2018 Term Loan
Debt Instrument [Line Items]
Total long-term debt, gross	126,563	136,875
Less – deferred financing costs	(1,155)	(1,715)
Total debt, net of unamortized discounts	125,408	135,160	$ 150,000
Senior Convertible Notes 2016
Debt Instrument [Line Items]
Total long-term debt, gross	230,000	230,000
Less – unamortized original issue discount	(3,021)	(6,004)
Less – deferred financing costs	(1,170)	(2,334)
Total debt, net of unamortized discounts	$ 225,809	$ 221,662