Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
Income Statement [Abstract]
Total revenue	$ 7,506,587	$ 7,122,086	$ 7,767,216
Cost of goods sold (exclusive of depreciation and amortization, shown separately below)	5,825,426	5,508,465	6,327,431
Gross profit	1,681,161	1,613,621	1,439,785
Operating expenses	1,172,328	1,053,805	960,424
Depreciation and amortization	197,629	170,937	156,111
Interest, net	41,536	40,173	41,225
Income before income taxes	269,668	348,706	282,025
Federal and state income taxes	92,183	122,724	101,397
Net income	$ 177,485	$ 225,982	$ 180,628
Net income per common share
Basic (in Dollars per share)	$ 4.54	$ 5.79	$ 4.66
Diluted (in Dollars per share)	4.48	5.73	4.62
Dividends declared (in Dollars per share)	$ 0.96	$ 0.88	$ 0.80