Share Repurchase Program (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		1 Months Ended			9 Months Ended	10 Months Ended
	Jun. 26, 2015	Feb. 28, 2015	Jan. 31, 2015	Oct. 31, 2014	May. 31, 2015	Jun. 30, 2015	Aug. 31, 2014
Share Repurchase Program [Line Items]
Shares repurchase authorized amount							$ 105.0
Shares acquired through stock repurchase program					2.9
Purchase of treasury stock					$ 95.3
Remaining amount authorized for repurchase through share repurchase program					$ 9.7
October 2014 Accelerated Share Repurchase Program [Member]
Share Repurchase Program [Line Items]
Shares repurchase authorized amount				$ 15.0
Shares acquired through stock repurchase program			0.0	0.6
Purchase of treasury stock				$ 15.0
Cash payment at completion of accelerated share repurchase program			$ 0.1
Final price paid per share			$ 26.32
February 2015 Accelerated Share Repurchase Program [Member]
Share Repurchase Program [Line Items]
Shares repurchase authorized amount		$ 75.0
Shares acquired through stock repurchase program		2.1
Purchase of treasury stock		$ 75.0
Subsequent Event [Member]
Share Repurchase Program [Line Items]
Shares acquired through stock repurchase program						3.2
Weighted-average price per share						$ 29.76
Subsequent Event [Member] | February 2015 Accelerated Share Repurchase Program [Member]
Share Repurchase Program [Line Items]
Shares acquired through stock repurchase program	0.3
Final price paid per share	$ 31.38