Commitments and Contingencies - Lease costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Lease cost
Operating lease cost	$ 1.2	$ 1.8	$ 3.8	$ 5.5
Variable lease cost	$ 0.3	$ 0.5	0.9	1.5
Operating cash flows from operating leases			$ 4.4	$ 5.7