Quarterly Consolidated Financial Information (Unaudited) - Schedule of Unaudited Quarterly Financial Data of Company (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
Feb. 28, 2018	Nov. 30, 2017	Aug. 31, 2017	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	May 31, 2016	Feb. 28, 2018	Feb. 28, 2017	Feb. 29, 2016
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 87,088	$ 93,606	$ 94,887	$ 94,590	$ 86,572	$ 88,660	$ 91,246	$ 90,410	$ 370,171	$ 356,888	$ 385,946
Gross profit margin	26,324	29,884	30,787	29,919	24,926	25,292	27,038	26,694	116,914	103,950	116,310
Net earnings	8,160	8,274	8,540	7,784	7,210	5,740	6,784	6,683	32,905	1,780	35,736
Dividends paid	$ 7,625	$ 5,083	$ 5,084	$ 4,468	$ 4,476	$ 4,537	$ 43,657	$ 4,530	$ 22,260	$ 57,200	$ 18,044
Per share of common stock:
Basic net earnings	$ 0.32	$ 0.33	$ 0.34	$ 0.31	$ 0.28	$ 0.22	$ 0.26	$ 0.26
Diluted net earnings	0.32	0.33	0.34	0.31	0.28	0.22	0.26	0.26
Dividends	$ 0.300	$ 0.200	$ 0.200	$ 0.175	$ 0.175	$ 0.175	$ 1.675	$ 0.175	$ 0.875	$ 2.20	$ 0.70

Aggregate dividends paid during the period for each share of common stock outstanding.

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