Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2017	Jul. 31, 2016
Income Statement [Abstract]
Total revenue	$ 2,093,739	$ 1,970,079
Cost of goods sold (exclusive of depreciation and amortization, shown separately below)	1,617,042	1,520,284
Operating expenses	321,247	292,128
Depreciation and amortization	52,369	45,855
Interest, net	11,375	10,540
Income before income taxes	91,706	101,272
Federal and state income taxes	34,948	33,880
Net income	$ 56,758	$ 67,392
Net income per common share
Basic (in dollars per share)	$ 1.48	$ 1.72
Diluted (in dollars per share)	$ 1.46	$ 1.70
Basic weighted average shares outstanding (in shares)	38,360,104	39,156,462
Plus effect of stock compensation (in shares)	480,184	474,677
Diluted weighted average shares outstanding (in shares)	38,840,288	39,631,139
Dividends declared per share (in dollars per share)	$ 0.26	$ 0.24