Note 13 - Quaterly Financial Data (Details) - Quaterly Financial Data (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																								6 Months Ended	9 Months Ended	12 Months Ended
	Apr. 30, 2014		Jan. 31, 2014		Oct. 31, 2013		Jul. 31, 2013		Apr. 30, 2013		Jan. 31, 2013		Oct. 31, 2012		Jul. 31, 2012		Apr. 30, 2012		Jan. 31, 2012		Oct. 31, 2011		Jul. 31, 2011		Oct. 31, 2013	Jan. 31, 2014	Apr. 30, 2014		Apr. 30, 2013		Apr. 30, 2012
Total revenue
Total revenue	$ 1,919,566		$ 1,790,055		$ 2,015,885		$ 2,114,749		$ 1,808,529		$ 1,662,365		$ 1,911,644		$ 1,868,302		$ 1,752,504		$ 1,578,950		$ 1,782,518		$ 1,873,832				$ 7,840,255		$ 7,250,840		$ 6,987,804
Gross profit*
Gross profit	283,620	[1]	276,690	[1]	319,285	[1]	342,421	[1]	263,666	[1]	246,870	[1]	276,458	[1]	284,075	[1]	242,605	[1]	227,840	[1]	262,918	[1]	266,782	[1]			1,222,016	[1]	1,071,069	[1]	1,000,145	[1]
Net income	20,932		12,653		39,430		53,795		21,604		13,757		31,146		37,307		21,509		16,162		37,632		39,391		93,225	105,878	126,820		103,814		114,694
Income per common share
Basic (in Dollars per share)	$ 0.54		$ 0.33		$ 1.03		$ 1.40		$ 0.56		$ 0.36		$ 0.81		$ 0.98		$ 0.56		$ 0.42		$ 0.99		$ 1.04		$ 2.43	$ 2.76	$ 3.30		$ 2.71		$ 3.01
Diluted (in Dollars per share)	$ 0.54		$ 0.33		$ 1.01		$ 1.39		$ 0.56		$ 0.36		$ 0.81		$ 0.97		$ 0.56		$ 0.42		$ 0.98		$ 1.03		$ 2.40	$ 2.73	$ 3.26		$ 2.69		$ 2.99
Gasoline [Member]
Total revenue
Total revenue	1,366,952		1,255,774		1,416,980		1,514,874		1,319,371		1,185,640		1,393,476		1,330,670		1,284,669		1,141,230		1,288,498		1,377,914				5,554,580		5,229,157		5,092,311
Gross profit*
Gross profit	52,937	[1]	55,892	[1]	67,816	[1]	91,227	[1]	61,561	[1]	49,186	[1]	54,779	[1]	55,896	[1]	46,736	[1]	48,270	[1]	62,688	[1]	65,320	[1]			267,872	[1]	221,422	[1]	223,014	[1]
Grocery and Other Merchandise [Member]
Total revenue
Total revenue	378,251		364,846		416,552		423,585		340,263		329,657		362,662		386,129		330,809		311,199		357,816		365,171				1,583,234		1,418,711		1,364,995
Gross profit*
Gross profit	121,387	[1]	113,429	[1]	134,708	[1]	138,412	[1]	107,963	[1]	104,660	[1]	121,206	[1]	128,834	[1]	109,196	[1]	99,099	[1]	116,221	[1]	118,729	[1]			507,936	[1]	462,663	[1]	443,245	[1]
Prepared Food and Fountain [Member]
Total revenue
Total revenue	162,977		158,200		171,751		166,248		138,642		137,033		146,540		142,709		128,281		118,750		128,838		123,483				659,176		564,924		499,712
Gross profit*
Gross profit	97,924	[1]	96,147	[1]	106,171	[1]	102,754	[1]	83,902	[1]	83,011	[1]	91,515	[1]	90,565	[1]	77,944	[1]	72,714	[1]	76,658	[1]	75,843	[1]			402,996	[1]	348,993	[1]	303,159	[1]
Other Segments [Member]
Total revenue
Total revenue	11,386		11,235		10,602		10,042		10,253		10,035		8,966		8,794		8,745		7,771		7,366		6,904				43,265		38,048		30,786
Gross profit*
Gross profit	$ 11,372	[1]	$ 11,222	[1]	$ 10,590	[1]	$ 10,028	[1]	$ 10,240	[1]	$ 10,013	[1]	$ 8,958	[1]	$ 8,780	[1]	$ 8,729	[1]	$ 7,757	[1]	$ 7,351	[1]	$ 6,890	[1]			$ 43,212	[1]	$ 37,991	[1]	$ 30,727	[1]

[1] Gross profit is given before charge for depreciation and amortization and credit card fees. Fiscal 2012 quarterly data was included for comparative purposes and to describe the impact of the immaterial error on Q3 and Q4 of 2012 as discussed in footnote 2, Correction of Immaterial Errors.