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, 2015	Nov. 30, 2014	Aug. 31, 2014	May 31, 2014	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	May 31, 2013	Feb. 28, 2015	Feb. 28, 2014	Feb. 28, 2013
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 140,242	$ 146,971	$ 151,841	$ 141,186	$ 132,138	$ 136,550	$ 135,288	$ 138,466	$ 580,240	$ 542,442	$ 533,506
Gross profit margin	35,384	36,516	38,188	35,388	33,580	37,759	36,659	35,795	145,476	143,793	124,152
Net earnings (loss)	8,598	(71,179)	10,016	8,032	(14,467)	9,349	9,801	8,506	(44,533)	13,189	24,715
Dividends paid	$ 4,502	$ 4,548	$ 4,574	$ 4,567	$ 4,590	$ 4,588	$ 4,587	$ 0	$ 18,191	$ 13,765	$ 22,864
Per share of common stock:
Basic net earnings (loss)	$ 0.34	$ (2.76)	$ 0.39	$ 0.31	$ (0.55)	$ 0.36	$ 0.38	$ 0.33	$ (1.72)	$ 0.50	$ 0.95
Diluted net earnings (loss)	$ 0.34	$ (2.76)	$ 0.39	$ 0.31	$ (0.55)	$ 0.36	$ 0.38	$ 0.33	$ (1.72)	$ 0.50	$ 0.95
Dividends	$ 0.175	$ 0.175	$ 0.175	$ 0.175	$ 0.175	$ 0.175	$ 0.175		$ 0.70	$ 0.53	$ 0.88