Treasury Stock (Details) - Schedule of repurchase of common stock (USD $)	1 Months Ended		12 Months Ended				44 Months Ended
	Sep. 30, 2010		May 31, 2014	May 31, 2013	May 31, 2012	Sep. 30, 2010	May 31, 2014
Stockholders' Equity Attributable to Parent [Abstract]
Authorized stock repurchase amount	$ 44,000,000.0	[1]				$ 200,000,000
Amount of stock repurchased in period			6,200,000	11,800,000	13,100,000		30,600,000
Remaining authorized repurchase amount			13,400,000
Shares of stock repurchased (in shares)			200,000			5,199,699
Average cost of stock repurchased (in Dollars per share)			$ 28.65			$ 30.00
Total cost of treasury stock acquired						$ 156,000,000

[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.