Quarterly Financial Data - Schedule of Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Total revenue
Total revenue	$ 1,582,954	$ 1,565,940	$ 1,924,600	$ 2,048,592	$ 1,653,858	$ 1,671,961	$ 2,150,211	$ 2,291,186	$ 7,122,086	$ 7,767,216	$ 7,840,255
Gross profit
Gross profit	388,220	371,169	442,990	411,242	346,543	351,046	371,282	370,914	1,613,621	1,439,785	1,222,016
Net income	$ 47,044	$ 38,099	$ 79,033	$ 61,806	$ 41,343	$ 39,319	$ 49,869	$ 50,097	$ 225,982	$ 180,628	$ 126,820
Net income per common share
Basic (in Dollars per share)	$ 1.20	$ 0.98	$ 2.03	$ 1.59	$ 1.06	$ 1.01	$ 1.29	$ 1.30	$ 5.79	$ 4.66	$ 3.30
Diluted (in Dollars per share)	$ 1.19	$ 0.97	$ 2.00	$ 1.57	$ 1.05	$ 1.01	$ 1.28	$ 1.28	$ 5.73	$ 4.62	$ 3.26
Fuel
Total revenue
Total revenue	$ 873,081	$ 888,744	$ 1,166,736	$ 1,286,241	$ 1,010,033	$ 1,056,458	$ 1,470,768	$ 1,607,126	$ 4,214,802	$ 5,144,385
Gross profit
Gross profit	85,828	85,460	122,690	87,681	75,228	98,418	89,637	87,872	381,659	351,155
Grocery & other merchandise
Total revenue
Total revenue	477,487	453,388	516,578	526,620	436,591	412,711	466,934	478,586	1,974,073	1,794,822
Gross profit
Gross profit	153,299	141,482	162,904	171,549	140,230	128,572	151,025	155,683	629,234	575,510
Prepared food & fountain
Total revenue
Total revenue	218,349	209,595	229,388	223,381	194,688	190,393	201,196	194,610	880,713	780,887
Gross profit
Gross profit	135,073	130,027	145,513	139,679	118,551	111,672	119,322	116,511	550,292	466,056
Other
Total revenue
Total revenue	14,037	14,213	11,898	12,350	12,546	12,399	11,313	10,864	52,498	47,122
Gross profit
Gross profit	$ 14,020	$ 14,200	$ 11,883	$ 12,333	$ 12,534	$ 12,384	$ 11,298	$ 10,848	$ 52,436	$ 47,064