Income Taxes - Income Tax from Continuing Operations (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current:
Federal	$ 17.1	$ 4.3	$ 8.0
State	2.1	0.8	2.1
Current	19.2	5.1	10.1
Deferred:
Federal	(8.0)	(10.5)	(6.3)
State	(2.7)	(2.2)	(2.8)
Deferred	(10.7)	(12.7)	(9.1)
Total continuing operations tax expense (benefit)	$ 8.5	$ (7.6)	$ 1.0