Stock Option Plan and Stock Based Compensation - Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended
	Feb. 28, 2015	Nov. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Shares, Options Outstanding, Beginning Balance		374,823
Number of Shares, Granted		43,426
Number of Shares, Terminated		(20,000)
Number of Shares, Exercised		0
Number of Shares, Options Outstanding, Ending Balance	374,823	398,249
Weighted Average Exercise Price, Beginning Balance		$ 15.95
Weighted Average Exercise Price, Granted		13.69
Weighted Average Exercise Price, Terminated		16.42
Weighted Average Exercise Price, Exercised		0
Weighted Average Exercise Price, Ending Balance	$ 15.95	$ 15.68
Weighted Average Remaining Contractual Life, Ending Balance	5 years 8 months 12 days	5 years 8 months 12 days
Aggregate Intrinsic Value, Beginning Balance		$ 210
Aggregate Intrinsic Value, Ending Balance	$ 210	$ 1,717
Number of Shares, Exercisable		321,824
Weighted Average Exercise Price, Exercisable		$ 16.00
Weighted Average Remaining Contractual Life, Exercisable		5 years
Aggregate Intrinsic Value, Exercisable		$ 1,283