Income Taxes - Unrecognized Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Uncertain tax position balance at beginning of year	$ 1.1	$ 1.0	$ 2.4
Increases related to current year tax positions	0.6	0.6	0.3
Increases related to prior year tax positions	0.0	0.0	0.4
Decreases related to prior year tax positions	0.0	(0.2)	(2.0)
Decreases related to expiration of statute of limitations	0.0	(0.3)	(0.1)
Uncertain tax position balance at end of year	$ 1.7	$ 1.1	$ 1.0