Convertible Senior Notes - 2024 Notes (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021	May 02, 2017
Debt Instrument [Line Items]
Net Carrying Amount	$ 377,700,000	$ 335,100,000
2.25% Convertible senior notes due 2024
Debt Instrument [Line Items]
Principal Amount	381,200,000	381,200,000	$ 517,500,000
Unamortized Debt, Discount	0	(43,200,000)
Unamortized Debt, Issuance Costs	(3,500,000)	(2,900,000)
Net Carrying Amount	377,700,000	335,100,000
Fair Value, Amount	$ 491,700,000	$ 464,700,000