Debt - 2023 notes Interest expense and carrying value (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Aug. 24, 2022	Dec. 31, 2021
Components of carrying value
Principal amount of debt	$ 1,370,500,000		$ 1,370,500,000			$ 1,430,700,000
Unamortized debt issuance cost	(10,861,000)		(10,861,000)			(15,718,000)
Carrying value	1,359,639,000		1,359,639,000			1,414,982,000
Components of interest expense
Borrowing interest expense	3,952,000
Amortization of debt issuance cost			3,010,000	$ 3,992,000
Accretion of original issue discount	176,000		(3,747,000)	(4,190,000)
Total interest and debt financing expenses	4,272,000
2023 Notes
Components of carrying value
Principal amount of debt						112,500
Unamortized debt issuance cost						(822)
Original issue discount, net of accretion						(545)
Carrying value					$ 112,500,000	$ 111,133
Components of interest expense
Borrowing interest expense	1,625	$ 2,520	6,219	8,895
Amortization of debt issuance cost	102	114	374	477
Accretion of original issue discount	67	76	248	316
Total interest and debt financing expenses	$ 1,794	$ 2,710	$ 6,841	$ 9,688