Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2017	Jan. 31, 2016
Income Statement [Abstract]
Net sales	$ 249,285	$ 218,632	$ 771,511	$ 706,122
Cost of sales and distribution	197,689	174,034	604,446	555,299
Gross Profit	51,596	44,598	167,065	150,823
Selling and marketing expenses	18,519	16,674	52,128	49,176
General and administrative expenses	11,476	9,183	33,083	30,647
Operating Income	21,601	18,741	81,854	71,000
Interest expense	447	119	776	230
Other income	(619)	(61)	(1,085)	(167)
Income Before Income Taxes	21,773	18,683	82,163	70,937
Income tax expense	7,220	6,670	28,312	25,586
Net Income	$ 14,553	$ 12,013	$ 53,851	$ 45,351
Weighted Average Shares Outstanding
Basic (in shares)	16,241,670	16,294,889	16,267,333	16,252,876
Diluted (in shares)	16,381,223	16,457,308	16,400,842	16,450,394
Net earnings per share
Basic (in usd per share)	$ 0.90	$ 0.74	$ 3.31	$ 2.79
Diluted (in usd per share)	$ 0.89	$ 0.73	$ 3.28	$ 2.76