Fair Value Disclosures (Fair Value Hierarchy, Carrying Values, and Estimated Fair Values of Financial Instruments) (Details) (USD $)
|
Jan. 29, 2013
Convertible senior notes due February 1, 2019 at 1.375%
|
May 31, 2013
Carrying Value
Level 2
|
Nov. 30, 2012
Carrying Value
Level 2
|
May 31, 2013
Estimate of Fair Value, Fair Value Disclosure [Member]
Level 2
|
Nov. 30, 2012
Estimate of Fair Value, Fair Value Disclosure [Member]
Level 2
|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | |||||
Estimated Fair Value | $ 1,671,194,000 | $ 1,670,504,000 | $ 1,895,795,000 | $ 1,831,596,000 | |
Convertible Debt, Fair Value Disclosures | 230,000,000 | 0 | 265,075,000 | 0 | |
Debt instrument, face amount | $ 230,000,000 | ||||
Debt Instrument, Interest Rate, Stated Percentage | 1.375% |