Stockholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended					6 Months Ended								6 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2013	May 31, 2012	May 31, 2013 Common Stock	May 31, 2012 Common Stock	Nov. 30, 2011 Common Stock	May 31, 2013 Paid-in Capital	May 31, 2012 Paid-in Capital	May 31, 2013 Retained Earnings	May 31, 2012 Retained Earnings	May 31, 2013 Accumulated Other Comprehensive Income	Nov. 30, 2012 Accumulated Other Comprehensive Income	May 31, 2012 Accumulated Other Comprehensive Income	Nov. 30, 2011 Accumulated Other Comprehensive Income	May 31, 2013 Grantor Stock Ownership Trust	May 31, 2012 Grantor Stock Ownership Trust	May 31, 2013 Treasury Stock	May 31, 2012 Treasury Stock	Nov. 30, 2011 Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 376,806	$ 442,657	$ 115,178	$ 115,171	$ 115,171	$ 888,579	$ 884,190	$ 450,292	$ 519,844	$ (27,958)	$ (27,958)	$ (26,152)	$ (26,152)	$ (115,149)	$ (118,059)	$ (934,136)	$ (932,337)	$ (932,337)
Net loss	(2,973)	(24,136)	(15,431)	(69,938)						(15,431)	(69,938)
Dividends on common stock			(4,179)	(6,746)						(4,179)	(6,746)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			1,517		113			1,404
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures			0					(325)								325
Restricted stock amortization			1,257	821				1,257	821
Stock-based compensation			787	2,384				787	2,384
Issuance of common stock			109,503					(106,622)										216,125
Grantor stock ownership trust			589	353				305	(133)							284	486
Treasury Stock, Value, Acquired, Cost Method			(33)															(33)
Ending balance	$ 470,816	$ 369,531	$ 470,816	$ 369,531	$ 115,291	$ 115,171	$ 115,171	$ 785,385	$ 887,262	$ 430,682	$ 443,160	$ (27,958)	$ (27,958)	$ (26,152)	$ (26,152)	$ (114,540)	$ (117,573)	$ (718,044)	$ (932,337)	$ (932,337)