Quarterly Consolidated Financial Information (Unaudited) - Schedule of Unaudited Quarterly Financial Data of Company (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	May 31, 2013	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	May 31, 2012	Feb. 28, 2014	Feb. 28, 2013	Feb. 29, 2012
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 132,138	$ 136,550	$ 135,288	$ 138,466	$ 123,638	$ 128,996	$ 138,344	$ 142,528	$ 542,442	$ 533,506	$ 517,014
Gross profit margin	33,580	37,759	36,659	35,795	31,343	30,611	33,949	28,249	143,793	124,152	130,513
Net earnings (loss)	(14,467)	9,349	9,801	8,506	7,074	6,170	7,592	3,879	13,189	24,715	31,358
Dividends paid	$ 4,590	$ 4,588	$ 4,587		$ 9,153	$ 4,576	$ 4,575	$ 4,560	$ 13,765	$ 22,864	$ 16,132
Per share of common stock:
Basic net earnings (loss)	$ (0.55)	$ 0.36	$ 0.38	$ 0.33	$ 0.27	$ 0.24	$ 0.29	$ 0.15	$ 0.50	$ 0.95	$ 1.21
Diluted net earnings (loss)	$ (0.55)	$ 0.36	$ 0.38	$ 0.33	$ 0.27	$ 0.24	$ 0.29	$ 0.15	$ 0.50	$ 0.95	$ 1.21
Dividends	$ 0.175	$ 0.175	$ 0.175		$ 0.350	$ 0.175	$ 0.175	$ 0.175	$ 0.53	$ 0.88	$ 0.62