UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
Net sales	$ 342,569	$ 326,657	$ 1,080,571	$ 996,622
Cost of sales	265,881	252,871	838,719	773,239
Gross profit	76,688	73,786	241,852	223,383
Selling, general, and administrative expenses	57,134	50,160	168,138	149,821
Depreciation and amortization	2,894	1,910	7,086	5,408
Interest and financing costs	270	409	903	1,158
Operating expenses	60,298	52,479	176,127	156,387
Operating income	16,390	21,307	65,725	66,996
Other income (expense)	(131)	0	(1)	380
Earnings before tax	16,259	21,307	65,724	67,376
Provision for income taxes	678	8,687	19,499	27,310
Net earnings	$ 15,581	$ 12,620	$ 46,225	$ 40,066
Net earnings per common share-basic (in dollars per share)	$ 1.12	$ 0.92	$ 3.34	$ 2.88
Net earnings per common share-diluted (in dollars per share)	$ 1.11	$ 0.91	$ 3.30	$ 2.86
Weighted average common shares outstanding-basic (in shares)	13,851	13,791	13,845	13,891
Weighted average common shares outstanding-diluted (in shares)	13,990	13,920	14,022	14,026