Income Taxes (Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current (benefit) expense:
Federal	$ (16.5)	$ 5.9	$ 6.4
State	0.4	0.7	0.6
Foreign	7.4	7.2	9.0
Total	(8.7)	13.8	16.0
Deferred expense (benefit):
Federal	6.7	1.8	1.3
State	(0.2)	(0.2)	0.1
Foreign	(0.3)	(0.2)	(0.8)
Total	6.2	1.4	0.6
Income tax (benefit) expense	$ (2.5)	$ 15.2	$ 16.6