Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Income Statement [Abstract]
Net sales	$ 274,769	$ 264,076	$ 551,596	$ 522,226
Cost of sales and distribution	217,434	207,924	435,767	406,757
Gross Profit	57,335	56,152	115,829	115,469
Selling and marketing expenses	18,077	17,146	36,230	33,609
General and administrative expenses	8,443	10,675	17,950	21,607
Operating Income	30,815	28,331	61,649	60,253
Interest expense	24	170	105	329
Other income	(672)	(269)	(1,291)	(466)
Income Before Income Taxes	31,463	28,430	62,835	60,390
Income tax expense	11,708	10,793	20,799	21,092
Net Income	$ 19,755	$ 17,637	$ 42,036	$ 39,298
Weighted Average Shares Outstanding
Basic (in shares)	16,197,088	16,295,948	16,234,746	16,280,164
Diluted (in shares)	16,268,078	16,440,321	16,319,224	16,410,652
Net earnings per share
Basic (in usd per share)	$ 1.22	$ 1.08	$ 2.59	$ 2.41
Diluted (in usd per share)	$ 1.21	$ 1.07	$ 2.58	$ 2.39