Share Repurchase Programs (Details) - Accelerated Share Repurchase Program [Member] - USD ($)	3 Months Ended				9 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2016
Equity, Class of Treasury Stock [Line Items]
Authorized amount				$ 300,000,000
Stock repurchase program expiration date				15 months
Remaining authorized repurchase amount	$ 91,500,000				$ 91,500,000
Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Repurchased amount	$ 60,500,000	$ 110,900,000	$ 37,100,000		$ 208,500,000
Shares repurchased	2,000,000.0	3,900,000.0	1,200,000.0		7,100,000.0