UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
Net sales	$ 336,286	$ 297,472	$ 606,152	$ 569,776
Cost of sales	264,365	233,548	475,101	449,413
Gross profit	71,921	63,924	131,051	120,363
Professional and other fees	1,513	1,577	3,031	3,410
Salaries and benefits	35,740	34,252	70,954	67,199
General and administrative expenses	7,585	7,158	14,364	13,431
Interest and financing costs	422	611	975	1,255
Operating expenses	45,260	43,598	89,324	85,295
Operating income	26,661	20,326	41,727	35,068
Other income	0	0	0	1,434
Earnings before tax	26,661	20,326	41,727	36,502
Provision for income taxes	10,982	8,374	17,234	15,073
Net earnings	$ 15,679	$ 11,952	$ 24,493	$ 21,429
Net earnings per common share-basic (In dollars per share)	$ 2.16	$ 1.63	$ 3.38	$ 2.88
Net earnings per common share-diluted (In dollars per share)	$ 2.15	$ 1.63	$ 3.35	$ 2.86
Weighted average common shares outstanding-basic (In shares)	7,274	7,320	7,249	7,412
Weighted average common shares outstanding-diluted (In shares)	7,297	7,345	7,310	7,461