UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
Net sales	$ 371,462	$ 336,286	$ 669,965	$ 606,152
Cost of sales	289,529	264,365	520,368	475,101
Gross profit	81,933	71,921	149,597	131,051
Professional and other fees	1,735	1,513	3,521	3,031
Salaries and benefits	42,296	35,740	82,094	70,954
General and administrative expenses	7,576	6,385	14,046	11,956
Depreciation and amortization	1,723	1,200	3,498	2,408
Interest and financing costs	400	422	749	975
Operating expenses	53,730	45,260	103,908	89,324
Operating income	28,203	26,661	45,689	41,727
Other income	380	0	380	0
Earnings before tax	28,583	26,661	46,069	41,727
Provision for income taxes	11,808	10,982	18,623	17,234
Net earnings	$ 16,775	$ 15,679	$ 27,446	$ 24,493
Net earnings per common share-basic (In dollars per share)	$ 2.43	$ 2.16	$ 3.94	$ 3.38
Net earnings per common share-diluted (In dollars per share)	$ 2.42	$ 2.15	$ 3.91	$ 3.35
Weighted average common shares outstanding-basic (In shares)	6,909	7,274	6,971	7,249
Weighted average common shares outstanding-diluted (In shares)	6,942	7,297	7,027	7,310