Income Taxes - Unrecognized Income Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Unrecognized Tax Benefits
Unrecognized tax benefits at beginning of the year	$ 1.9	$ 2.4	$ 2.3
Additions (reductions) for tax positions taken during the prior period	0.4
Additions (reductions) for tax positions taken during the prior period		(0.6)	(0.1)
Additions for tax positions taken during the current period	0.0	0.2	0.2
Reductions relating to settlements with taxing authorities	0.0	(0.1)	0.0
Lapse of statutes of limitation	(0.6)	0.0	0.0
Unrecognized tax benefits at end of the year	$ 1.7	$ 1.9	$ 2.4