Quaterly Financial Data - Schedule of Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013
Total revenue
Total revenue	$ 1,653,858	$ 1,671,961	$ 2,150,211	$ 2,291,186	$ 1,919,566	$ 1,790,055	$ 2,015,885	$ 2,114,749	$ 7,767,216	$ 7,840,255	$ 7,250,840
Gross profit
Gross profit	346,543	351,046	371,282	370,914	283,620	276,690	319,285	342,421	1,439,785	1,222,016	1,071,069
Net income	$ 41,343	$ 39,319	$ 49,869	$ 50,097	$ 20,932	$ 12,663	$ 39,430	$ 53,795	$ 180,628	$ 126,820	$ 103,814
Net income per common share
Basic (in Dollars per share)	$ 1.06	$ 1.01	$ 1.29	$ 1.30	$ 0.54	$ 0.33	$ 1.03	$ 1.40	$ 4.66	$ 3.30	$ 2.71
Diluted (in Dollars per share)	$ 1.05	$ 1.01	$ 1.28	$ 1.28	$ 0.54	$ 0.33	$ 1.01	$ 1.39	$ 4.62	$ 3.26	$ 2.69
Fuel
Total revenue
Total revenue	$ 1,010,033	$ 1,056,458	$ 1,470,768	$ 1,607,126	$ 1,366,952	$ 1,255,774	$ 1,416,980	$ 1,514,874	$ 5,144,385	$ 5,554,580
Gross profit
Gross profit	75,228	98,418	89,637	87,872	52,937	55,892	67,816	91,227	351,155	267,872
Grocery & Other Merchandise
Total revenue
Total revenue	436,591	412,711	466,934	478,586	378,251	364,846	416,552	423,585	1,794,822	1,583,234
Gross profit
Gross profit	140,230	128,572	151,025	155,683	121,387	113,429	134,708	138,412	575,510	507,936
Prepared Food & Fountain
Total revenue
Total revenue	194,688	190,393	201,196	194,610	162,977	158,200	171,751	166,248	780,887	659,176
Gross profit
Gross profit	118,551	111,672	119,322	116,511	97,924	96,147	106,171	102,754	466,056	402,996
Other
Total revenue
Total revenue	12,546	12,399	11,313	10,864	11,386	11,235	10,602	10,042	47,122	43,265
Gross profit
Gross profit	$ 12,534	$ 12,384	$ 11,298	$ 10,848	$ 11,372	$ 11,222	$ 10,590	$ 10,028	$ 47,064	$ 43,212