Long‑Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total long-term debt	$ 1,302,845	$ 246,000
Convertible Debt | 2026 Notes:
Debt Instrument [Line Items]
Long-term debt, gross	690,000	0
Unamortized debt issuance costs	(15,585)	0
Total long-term debt	674,415	0
Convertible Debt | 2027 Notes:
Debt Instrument [Line Items]
Long-term debt, gross	575,000	0
Unamortized debt issuance costs	(14,424)	0
Total long-term debt	560,576	0
Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Long-term debt, gross	$ 67,854	$ 246,000