Debt - Long-Term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Less - unamortized original issue discount	$ (1,017)	$ (5,346)
Total debt, net of unamortized discounts	349,614	351,217
Current portion of long-term debt, net of unamortized discounts	(241,881)	(14,063)
Long-term debt, net of unamortized discounts	107,733	337,154
2018 Credit Agreement | 2018 Term Loan
Debt Instrument [Line Items]
Total long-term debt, gross	123,750	126,563
Less – deferred financing costs	(1,017)	(1,155)
Total debt, net of unamortized discounts	122,733	125,408
Senior Convertible Notes 2016
Debt Instrument [Line Items]
Total long-term debt, gross	230,000	230,000
Less - unamortized original issue discount	(2,249)	(3,021)
Less – deferred financing costs	(870)	(1,170)
Total debt, net of unamortized discounts	226,881	$ 225,809
Current portion of long-term debt, net of unamortized discounts	$ (226,900)