Short-Term Borrowings (Details) (USD $)	11 Months Ended	12 Months Ended
	Nov. 30, 2010	Nov. 30, 2011	Nov. 12, 2011	Aug. 31, 2011	Feb. 28, 2011	Aug. 31, 2011 Short-term Debt [Member]	Jul. 01, 2011 Short-term Debt [Member]
Extinguishment of Debt [Line Items]
Revolving credit facility		$ 950,000,000	$ 950,000,000		$ 1,000,000,000		$ 1,000,000,000
Borrowings outstanding under the Credit Facility	0	0		100,000,000		195,700,000
Short-Term Borrowings (Textual) [Abstract]
Average daily bank loans	23,800,000	12,000,000
Outstanding unsecured or secured bank loans	$ 0	$ 52,721,000