Stockholders' Equity - Per Share Results (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2019	Aug. 31, 2018
Earnings per share:
Net income (loss)	$ 1,017	$ (122)	$ 6,250	$ (1,514)
Weighted average shares outstanding for computation of basic per share results	5,073,000	5,031,000	5,068,000	5,013,000
Incremental shares from assumed exercise of Griffin stock options	40,000		34,000
Adjusted weighted average shares for computation of diluted per share results	5,113,000	5,031,000	5,102,000	5,013,000
Incremental shares from assumed exercise of stock options excluded due to anti-dilutive effect		76,000		60,000