Other Assets (Details) (USD $)	May 31, 2013		Mar. 12, 2013	Nov. 30, 2012		Jan. 29, 2013 Convertible senior notes due February 1, 2019 at 1.375%
Other Assets [Abstract]
Cash surrender value of insurance contracts	$ 67,634,000			$ 64,757,000
Debt issuance costs	22,952,000	[1]		14,563,000	[1]
Property and equipment, net	7,736,000			7,920,000
Prepaid expenses	5,475,000			7,810,000
Total	103,797,000			95,050,000
Debt Instrument [Line Items]
Debt instrument, face amount						230,000,000
Unsecured revolving credit facility, current borrowing capacity			$ 200,000,000.0

[1] The increase in debt issuance costs as of May 31, 2013 compared to November 30, 2012 primarily reflected the costs associated with our underwritten public issuance of the $230 Million Convertible Senior Notes during the first quarter of 2013 and our entry into a $200.0 million unsecured revolving credit facility (the “Credit Facility”) during the second quarter of 2013.