Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns
Balance as of the beginning of the year	$ 2.3	$ 2.0	$ 1.8
Increases related to prior year tax positions	0.0	0.2	0.1
Decreases related to prior year tax positions	(0.1)	0.0	0.0
Increases related to current year tax positions	0.0	0.1	0.1
Settlements	0.0	0.0	0.0
Lapse of statute	(0.5)	0.0	0.0
Balance as of the end of the year	$ 1.7	$ 2.3	$ 2.0