Income Taxes - Roll Forward of Unrecognized Tax Benefits and Associated Interest and Penalties Included in Balance Sheet (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 3.4	$ 2.8
Balance	3.4	4.4
Unrecognized Tax Benefits, Period Increase (Decrease)	0.4	(0.5)
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities		(0.8)
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations		0.3
Increase in current year tax positions	0.3
Balance	4.1	3.4
Gross Unrecognized Tax Benefits, Excluding Interest and Penalties
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Balance	3.1	4.1
Unrecognized Tax Benefits, Period Increase (Decrease)	0.3	(0.6)
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities		(0.7)
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations		0.3
Increase in current year tax positions	0.3
Balance	3.7	3.1
Interest and Penalties
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Balance	0.3	0.3
Unrecognized Tax Benefits, Period Increase (Decrease)	0.1	0.1
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities		(0.1)
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations		0.0
Increase in current year tax positions	0.0
Balance	$ 0.4	$ 0.3