Subsequent Event/Senior Notes Payable (Details Textual) (USD $)	1 Months Ended	3 Months Ended
	Feb. 29, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Feb. 07, 2012 5.875 % senior notes due 2022 [Member]	Feb. 07, 2012 Senior notes issued for cash [Member]	Mar. 05, 2012 Senior notes issued through an exchange [Member]	Mar. 31, 2012 6.875% Senior notes due 2012 [Member]	Mar. 05, 2012 6.875% Senior notes due 2012 [Member]	Mar. 31, 2012 5.95% Senior notes due 2013 [Member]	Mar. 05, 2012 5.95% Senior notes due 2013 [Member]
Senior Note Payable (Textual) [Abstract]
Issued Senior Notes			$ 1,491,442,000	$ 1,490,972,000		$ 300,000,000	$ 119,900,000
Interest rate on notes					5.875%			6.875%		5.95%
Proceeds from issuance of the Senior Notes	296,200,000
Senior Notes Exchanged									80,700,000		36,900,000
Costs associated with the exchange of both series of notes		$ 1,100,000