Debt - October 2026 notes Interest expense and carrying value (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Components of carrying value
Principal amount of debt		$ 1,498,500		$ 1,498,500		$ 1,395,500
Unamortized debt issuance cost		(8,893)		(8,893)		(10,197)
Carrying value	[1]	1,489,607		1,489,607		1,385,303
Components of interest expense
Amortization of debt issuance cost				1,770	$ 2,001
Accretion of original issue discount				(3,151)	(2,694)
October 2026 Notes
Components of carrying value
Principal amount of debt		300,000		300,000		300,000
Unamortized debt issuance cost		(2,403)		(2,403)		(2,765)
Original issue discount, net of accretion		(2,105)		(2,105)		(2,423)
Carrying value	[1]	295,492		295,492		$ 294,812
Components of interest expense
Borrowing interest expense		1,912	$ 1,913	3,825	3,825
Amortization of debt issuance cost		182	182	362	362
Accretion of original issue discount		159	159	317	317
Total interest and debt financing expenses		$ 2,253	$ 2,254	$ 4,504	$ 4,504

[1] Carrying value represents aggregate principal amount outstanding less unamortized debt issuance costs.