Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Income Statement [Abstract]
Net sales	$ 264,076	$ 256,292	$ 522,226	$ 487,490
Cost of sales and distribution	207,924	200,240	406,757	381,265
Gross Profit	56,152	56,052	115,469	106,225
Selling and marketing expenses	17,146	16,783	33,609	32,502
General and administrative expenses	10,675	10,733	21,607	21,464
Operating Income	28,331	28,536	60,253	52,259
Interest expense	170	57	329	111
Other income	(269)	(54)	(466)	(106)
Income Before Income Taxes	28,430	28,533	60,390	52,254
Income tax expense	10,793	10,353	21,092	18,916
Net Income	$ 17,637	$ 18,180	$ 39,298	$ 33,338
Weighted Average Shares Outstanding
Basic (in shares)	16,295,948	16,282,881	16,280,164	16,231,870
Diluted (in shares)	16,440,321	16,472,645	16,410,652	16,446,937
Net earnings per share
Basic (in usd per share)	$ 1.08	$ 1.12	$ 2.41	$ 2.05
Diluted (in usd per share)	$ 1.07	$ 1.10	$ 2.39	$ 2.03