Stockholders' Equity (Details 2) - 2009 Stock Option Plan - $ / shares	6 Months Ended
	May. 31, 2015	May. 31, 2014
Activity under the Griffin Stock Option Plan
Outstanding at beginning of period (in shares)	222,001	239,677
Granted (in shares)	8,282	8,532
Exercised (in shares)	(3,134)	(3,208)
Forfeited (in shares)		(23,000)
Outstanding at end of period (in shares)	227,149	222,001
Weighted Avg. Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 30.35	$ 30.35
Granted (in dollars per share)	31.38	28.12
Exercised (in dollars per share)	25.53	24.94
Forfeited (in dollars per share)		30.27
Outstanding at end of period (in dollars per share)	$ 30.45	$ 30.35