Quarterly Financial Data - Schedule of Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017
Total revenue
Total revenue	$ 2,178,397	$ 2,048,076	$ 2,538,005	$ 2,588,432	$ 2,089,037	$ 2,054,603	$ 2,153,745	$ 2,093,739	$ 9,352,910	$ 8,391,124	$ 7,506,587
Gross profit
Gross profit	452,370	470,265	510,321	521,768	405,115	419,924	467,657	476,697	1,954,724	1,769,393
Net income	$ 25,212	$ 41,835	$ 66,615	$ 70,224	$ 19,262	$ 192,965	$ 48,918	$ 56,758	$ 203,886	$ 317,903	$ 177,485
Net income per common share
Basic (in Dollars per share)	$ 0.69	$ 1.14	$ 1.82	$ 1.92	$ 0.52	$ 5.13	$ 1.29	$ 1.48	$ 5.55	$ 8.41	$ 4.54
Diluted (in Dollars per share)	$ 0.68	$ 1.13	$ 1.80	$ 1.90	$ 0.51	$ 5.08	$ 1.28	$ 1.46	$ 5.51	$ 8.34	$ 4.48
Fuel
Total revenue
Total revenue	$ 1,345,866	$ 1,233,620	$ 1,621,868	$ 1,647,417	$ 1,321,417	$ 1,297,340	$ 1,306,246	$ 1,220,985	$ 5,848,770	$ 5,145,988
Gross profit
Gross profit	101,417	122,559	118,656	123,476	86,640	100,272	110,686	109,212	466,107	406,811
Grocery & other merchandise
Total revenue
Total revenue	562,699	543,773	618,250	644,800	511,834	502,750	572,151	597,413	2,369,521	2,184,147
Gross profit
Gross profit	177,188	173,512	200,193	208,925	159,929	160,150	183,133	190,364	759,817	693,576
Prepared food & fountain
Total revenue
Total revenue	254,086	256,144	283,062	281,003	241,163	240,618	261,998	261,840	1,074,294	1,005,621
Gross profit
Gross profit	158,057	159,682	176,675	174,184	143,949	145,632	160,510	163,645	668,598	613,736
Other
Total revenue
Total revenue	15,746	14,539	14,825	15,212	14,623	13,895	13,350	13,501	60,325	55,368
Gross profit
Gross profit	$ 15,708	$ 14,512	$ 14,797	$ 15,183	$ 14,597	$ 13,870	$ 13,328	$ 13,476	$ 60,202	$ 55,270