Fair Value Disclosures (Details 1) (USD $) In Thousands	Aug. 31, 2011	Nov. 30, 2010
Debt Instrument [Line Items]
Carrying Value	$ 1,586,703	$ 1,775,529
Senior notes due 2011 at 6 3/8% [Member]
Debt Instrument [Line Items]
Carrying Value	0	99,916
Estimated Fair Value	0	101,500
Senior notes due 2014 at 5 3/4% [Member]
Debt Instrument [Line Items]
Carrying Value	249,609	249,498
Estimated Fair Value	236,875	246,250
Senior notes due 2015 at 5 7/8% [Member]
Debt Instrument [Line Items]
Carrying Value	299,221	299,068
Estimated Fair Value	261,000	289,500
Senior notes due 2015 at 6 1/4% [Member]
Debt Instrument [Line Items]
Carrying Value	449,782	449,745
Estimated Fair Value	389,250	435,375
Senior notes due 2017 at 9.1% [Member]
Debt Instrument [Line Items]
Carrying Value	260,732	260,352
Estimated Fair Value	237,175	279,575
Senior notes due 2018 at 7 1/4% [Member]
Debt Instrument [Line Items]
Carrying Value	298,978	298,893
Estimated Fair Value	$ 254,250	$ 286,500