Share Repurchase Program (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended		6 Months Ended	1 Months Ended
	Jan. 31, 2014	Aug. 31, 2013	Feb. 28, 2014	Feb. 28, 2014 Accelerated Share Repurchase Program [Member]	Apr. 04, 2014 Subsequent Event [Member] Accelerated Share Repurchase Program [Member]
Share Repurchase Program [Line Items]
Shares repurchase authorized amount increase	$ 40.0
Shares repurchase authorized amount		40.0	80.0	40.0
Shares acquired through stock repurchase program			3.1	2.1	0
Purchase of treasury stock			58.4	40.0
Remaining amount authorized for repurchase through share repurchase program			$ 21.6
Final price paid per share					$ 19.13
Weighted-average price per share			$ 19.06