Commitments and Contingencies Commitments and Contingencies (Schedule of Future Minimum Rental Payments for Operating Leases) (Details) (USD $)	12 Months Ended
	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2010
Operating Leased Assets [Line Items]
2013	$ 5,873,000
2014	5,338,000
2015	2,728,000
2016	289,000
2017	0
Thereafter	0
Total Minimum Lease Payments	14,228,000
Rental expense on operating leases	$ 5,500,000	$ 6,700,000	$ 8,500,000
Minimum
Operating Leased Assets [Line Items]
Noncancelable operating leases, term	3 years
Maximum
Operating Leased Assets [Line Items]
Noncancelable operating leases, term	5 years
Noncancelable operating leases, renewal term	5 years