Earnings per Share - Computation for Basic and Diluted Earnings (loss) per Share (Detail) - $ / shares	3 Months Ended		6 Months Ended
	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2018	Aug. 31, 2017
Earnings Per Share [Abstract]
Basic weighted average common shares outstanding	25,671,643	25,342,747	25,510,356	25,388,292
Effect of dilutive options	13,871	23,254	12,475	17,571
Diluted weighted average common shares outstanding	25,685,514	25,366,001	25,522,831	25,405,863
Earnings per share
Net earnings - basic	$ 0.37	$ 0.34	$ 0.74	$ 0.64
Net earnings - diluted	0.37	0.34	0.74	0.64
Cash dividends	$ 0.225	$ 0.200	$ 0.425	$ 0.375