Earnings (Loss) Per Share (Calculation of Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Nov. 30, 2017	Aug. 31, 2017	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	May 31, 2016	Feb. 29, 2016	Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2015
Earnings Per Share [Abstract]
Net income (loss)	$ 16,429	$ 11,172	$ 10,341	$ (525)	$ (73,793)	$ 7,576	$ 7,275	$ 3,216	$ 37,417	$ (55,726)	$ (8,801)
Weighted average shares outstanding (in shares)									48,129	49,481	50,391
Dilutive impact from common stock equivalents (in shares)									387	0	0
Diluted weighted average shares outstanding (in shares)									48,516	49,481	50,391
Basic earnings (loss) per share (in dollars per share)	$ 0.35	$ 0.23	$ 0.21	$ (0.01)	$ (1.52)	$ 0.16	$ 0.15	$ 0.06	$ 0.78	$ (1.13)	$ (0.17)
Diluted earnings (loss) per share (in dollars per share)	$ 0.34	$ 0.23	$ 0.21	$ (0.01)	$ (1.52)	$ 0.15	$ 0.14	$ 0.06	$ 0.77	$ (1.13)	$ (0.17)