Income Taxes (Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current expense (benefit):
Federal	$ 6.4	$ 14.3	$ (0.8)
State	0.6	0.7	0.2
Foreign	9.0	7.6	6.6
Total	16.0	22.6	6.0
Deferred expense (benefit):
Federal	1.3	(5.4)	1.6
State	0.1	0.3	0.5
Foreign	(0.8)	0.7	0.7
Total	0.6	(4.4)	2.8
Income tax expense	$ 16.6	$ 18.2	$ 8.8