Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 31, 2015	Aug. 31, 2014	Aug. 31, 2015	Aug. 31, 2014
Numerator:
Net income (loss)	$ (3,956)	$ 191	$ 24,352	$ 41,555
Denominator:
Weighted average shares outstanding	46,647,480	46,593,133	46,611,656	46,548,078
Effect of dilutive securities	0	13,527	14,567	14,004
Diluted weighted average shares outstanding	46,647,480	46,606,660	46,626,223	46,562,082
Basic and diluted earnings (loss) per share
Basic and diluted (loss) earnings per share (in dollars per share)	$ (0.08)	$ 0.00	$ 0.52	$ 0.89
Anti-dilutive shares excluded in the computation of diluted earnings per share	152,896	114,302	101,436	125,560