Treasury Stock (Details) - USD ($)	3 Months Ended	12 Months Ended		60 Months Ended
	Aug. 31, 2015	Sep. 30, 2010		Aug. 31, 2015	Jul. 22, 2015	Oct. 01, 2009
Stockholders' Equity Attributable to Parent [Abstract]
Authorized stock purchase amount		$ 44,000,000	[1]			$ 200,000,000
Treasury stock acquired (in shares)		5,199,699
Treasury stock acquired (in dollars per sahre)		$ 30.00
Treasury stock acquired	$ 0	$ 156,000,000		$ 34,100,000
Increase in authorized amount of stock to be repurchased					$ 50,000,000

[1] Represents the remainder of a $200.0 authorization after giving effect to the purchase of 5,199,699 shares at $30.00 per share pursuant to a large share repurchase in the form of a modified Dutch auction tender offer that was completed by the Company on November 3, 2010 for a total cost of $156.0 , excluding related fees and expenses.