Stockholders' Equity - Per Share Results (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2020	May 31, 2019
Earnings per share:
Net (loss) income	$ (693)	$ 5,819	$ (1,013)	$ 5,233
Weighted average shares outstanding for computation of basic per share results	5,125,000	5,067,000	5,100,000	5,066,000
Incremental shares from assumed exercise of Griffin stock options		40,000		31,000
Adjusted weighted average shares for computation of diluted per share results	5,125,000	5,107,000	5,100,000	5,097,000
Incremental shares from assumed exercise of stock options excluded due to anti-dilutive effect			43,000	49,000