Income Taxes (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Provision at the U.S. statutory rate of 35%	$ 96.0	$ 70.6	$ 58.6
Increase (reduction) in tax expense resulting from:
State income tax, net of federal income tax benefit	7.1	5.9	2.9
Effective Income Tax Rate Reconciliation, Deduction, Other, Amount	(6.4)	(3.1)	(3.5)
Research tax credit	(0.5)	0	(0.3)
Effective Income Tax Rate Reconciliation, Tax Contingency, Other, Amount	0.7	(5.1)	(0.6)
Change in valuation allowance	0.7	2.3	(0.7)
Foreign taxes at rates other than 35% and miscellaneous other	(3.2)	(3.9)	(0.6)
Total income tax provision	$ 94.4	$ 66.7	$ 55.8