EARNINGS PER SHARE Computation of Basic and Diluted Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Nov. 30, 2013	Aug. 31, 2013	May 31, 2013	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	May 31, 2012	Feb. 29, 2012	Nov. 30, 2013	Nov. 30, 2012	Nov. 30, 2011
Earnings Per Share [Abstract]
Net income	$ 17,205	$ (7,866)	$ 22,440	$ 13,513	$ 24,736	$ (1,037)	$ 13,740	$ 17,139	$ 45,292	$ 54,578	$ 69,424
Denominator:
Weighted average shares outstanding									46,470,647	46,386,355	47,602,574
Common stock options									15,914	10,276	8,605
Diluted weighted average shares outstanding									46,486,561	46,396,631	47,611,179
Diluted earnings per share:
Basic and diluted earnings per share									$ 0.97	$ 1.18	$ 1.46
Anti-dilutive shares excluded in the computation of diluted earnings per share									143,656	231,496	254,945