Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Income Statement [Abstract]
Total revenue	[1]	$ 2,538,005	$ 2,153,745	$ 5,126,437	$ 4,247,484
Cost of goods sold (exclusive of depreciation and amortization, shown separately below)	[1]	2,027,684	1,686,088	4,094,348	3,303,130
Operating expenses		344,186	322,949	703,578	644,196
Depreciation and amortization		61,356	54,157	120,196	106,526
Interest, net		14,191	12,976	28,597	24,351
Income before income taxes		90,588	77,575	179,718	169,281
Federal and state income taxes		23,973	28,657	42,879	63,605
Net income		$ 66,615	$ 48,918	$ 136,839	$ 105,676
Net income per common share
Basic (in dollars per share)		$ 1.82	$ 1.29	$ 3.73	$ 2.77
Diluted (in dollars per share)		$ 1.80	$ 1.28	$ 3.70	$ 2.75
Basic weighted average shares outstanding (in shares)		36,698,528	37,804,649	36,683,450	38,108,105
Plus effect of stock compensation (in shares)		318,943	378,950	314,181	379,802
Diluted weighted average shares outstanding (in shares)		37,017,471	38,183,599	36,997,631	38,487,907
Dividends declared per share (in dollars per share)		$ 0.29	$ 0.26	$ 0.58	$ 0.52
Excise taxes		$ 255,114	$ 239,070	$ 513,083	$ 477,628

[1] Includes excise taxes of: $255,114, $239,070, $513,083 and $477,628