Debt (Details) (USD $)	3 Months Ended		9 Months Ended
	May 31, 2011	Feb. 28, 2011	May 31, 2011
Debt [Abstract]
Gain (loss) from early extinguishment of debt	$ (28,230,000)	$ 5,200,000	$ (23,025,000)
Prepayment premium and write-off of unamortized deferred loan fees	25,300,000
Amount of debt repurchased		$ 62,500,000