Stockholders' Equity - Per Share Results (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2018	Aug. 31, 2017
Earnings per share:
Net (loss) income	$ (122)	$ 1,329	$ (1,514)	$ 5,117
Weighted average shares outstanding for computation of basic per share results	5,031,000	5,001,000	5,013,000	5,013,000
Incremental shares from assumed exercise of Griffin stock options		27,000		24,000
Adjusted weighted average shares for computation of diluted per share results	5,031,000	5,028,000	5,013,000	5,037,000
Incremental shares from assumed exercise of stock options excluded due to anti-dilutive effect	76,000		60,000