Stockholders' Equity - Per Share Results (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	May 31, 2019	May 31, 2018	May 31, 2019	May 31, 2018
Earnings per share:
Net income (loss)	$ 5,819	$ 331	$ 5,233	$ (1,392)
Weighted average shares outstanding for computation of basic per share results	5,067,000	5,006,000	5,066,000	5,003,000
Incremental shares from assumed exercise of Griffin stock options	40,000	57,000	31,000
Adjusted weighted average shares for computation of diluted per share results	5,107,000	5,063,000	5,097,000	5,003,000
Incremental shares from assumed exercise of stock options excluded due to anti-dilutive effect				53,000