Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Income Statement [Abstract]
Net sales	$ 947,045	$ 825,465	$ 726,515
Cost of sales and distribution	747,351	672,933	602,338
Gross Profit	199,694	152,532	124,177
Selling and marketing expenses	66,489	64,304	59,536
General and administrative expenses	40,045	33,773	30,881
Restructuring charges, net	0	(240)	(234)
Insurance proceeds	0	0	(94)
Operating Income	93,160	54,695	34,088
Interest expense	378	515	728
Other income	996	(207)	(310)
Income Before Income Taxes	91,786	54,387	33,670
Income tax expense	33,063	18,888	13,209
Net Income	$ 58,723	$ 35,499	$ 20,461
Earnings per share
Basic (usd per share)	$ 3.61	$ 2.25	$ 1.34
Diluted (usd per share)	$ 3.57	$ 2.21	$ 1.31