Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2015	Jul. 31, 2014
Income Statement [Abstract]
Total revenue	$ 2,048,592	$ 2,291,186
Cost of goods sold (exclusive of depreciation and amortization, shown separately below)	1,637,350	1,920,272
Gross profit	411,242	370,914
Operating expenses	263,582	244,318
Depreciation and amortization	39,399	36,249
Interest, net	10,084	10,506
Income before income taxes	98,177	79,841
Federal and state income taxes	36,371	29,744
Net income	$ 61,806	$ 50,097
Net income per common share
Basic (in dollars per share)	$ 1.59	$ 1.30
Diluted (in dollars per share)	$ 1.57	$ 1.28
Basic weighted average shares outstanding (in shares)	38,964,765	38,616,340
Plus effect of stock compensation (in shares)	420,727	390,121
Diluted weighted average shares outstanding (in shares)	39,385,492	39,006,461