Stockholders' Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended			1 Months Ended	3 Months Ended		9 Months Ended			0 Months Ended
	Aug. 03, 2012	May 03, 2012	Feb. 03, 2012	May 31, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Feb. 02, 2010	Nov. 01, 2012 Subsequent Event [Member]
Class of Stock [Line Items]
Common stock, dividends, per share, declared	$ 0.17	$ 0.17	$ 0.17							$ 0.19
Dividend declared and paid, common shares							$ 5.9	$ 0
Stock repurchase program, authorized amount				30
Line of credit facility, funds for future share repurchases									30
Common stock repurchased under repurchase program, shares					0	345,467	17,800	517,067
Common stock repurchased, average price per share						$ 34.88	$ 39.50	$ 34.81
Common stock repurchased, amount						12.0	0.7	18.0
Common stock available for future share repurchases, amount							$ 10.3