Stockholders' Equity - Per Share Results (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2018	May 31, 2017
Earnings per share:
Net income (loss)	$ 331	$ 4,727	$ (1,392)	$ 3,788
Weighted average shares outstanding for computation of basic per share results	5,006,000	5,001,000	5,003,000	5,020,000
Incremental shares from assumed exercise of Griffin stock options	57,000	22,000		23,000
Adjusted weighted average shares for computation of diluted per share results	5,063,000	5,023,000	5,003,000	5,043,000
Incremental shares from assumed exercise of stock options excluded due to anti-dilutive effect				53,000