Income Taxes (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Income Taxes
U.S. federal statutory rate	35.00%
Effective income tax rate	30.60%
Income before income taxes, domestic operations	$ 47.2	$ 82.5
Income before income taxes, foreign operations	50.5	(3.2)
Liabilities for uncertain income tax positions	28.2		37.9
Cash paid for income taxes	8.1
Prepaid tax payments	$ 12.3		$ 7.5