Segment Information - Reconciliation of Total Segment Profits to Consolidated Totals (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reconciliation [Abstract]
Net income	$ 9.0	$ 8.7	$ 9.4	$ 20.4	$ 17.7	$ 29.8
Net loss (income) attributable to noncontrolling interest	0.0		(0.1)		0.0	0.1
Net income attributable to controlling interest	9.0		9.3		17.7	29.9
Operating Segments
Segment Reconciliation [Abstract]
Net income	24.6		22.7		52.1	45.9
Net income attributable to controlling interest	8.7		9.1		17.4	29.4
Intersegment Eliminations
Segment Reconciliation [Abstract]
Net income	0.3		0.3		0.3	0.4
Corporate
Segment Reconciliation [Abstract]
Net income	$ (15.9)		$ (13.6)		$ (34.7)	$ (16.5)