Income Taxes (Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current expense:
Federal	$ 11.7	$ 17.4	$ 16.0
State	0.7	0.8	1.5
Foreign	6.0	6.2	4.2
Total	18.4	24.4	21.7
Deferred expense (benefit):
Federal	2.7	1.0	1.2
State	0.6	(0.8)	(2.6)
Foreign	(0.4)	0.3	(0.9)
Total	2.9	0.5	(2.3)
Income tax expense	$ 21.3	$ 24.9	$ 19.4