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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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The excise taxes collected by a public utility and reported in revenues if the amount of excise taxes is equal to 1 percent or more of such total.

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Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
Significant Accounting Policies (Details) $ in Thousands	Apr. 30, 2020 USD ($) people state segment merchandise_category store	Apr. 30, 2019 USD ($)	Apr. 30, 2018 USD ($)	May 01, 2018 USD ($)	Apr. 30, 2017 USD ($)
Accounting Policies [Abstract]
Number of stores \| store	2,207
Number of states in which entity operates \| state	16
Population of communities (many less than) \| people	5,000
Concentration Risk
Shareholders' equity	$ 1,643,205	$ 1,408,769	$ 1,271,141		$ 1,190,620
Deferred income taxes	435,598	385,788
Excess of current cost over the stated LIFO Value	87,546	80,814
Goodwill	161,075	157,223
Asset impairment charges	1,177	1,167	507
Excise taxes collected	1,063,000	988,000	$ 919,000
Contract liability	11,180	6,931
Recorded asset retirement obligation (net of amortization)	13,416	11,793
Discounted liability of asset retirement obligation	22,658	18,058
Self insurance reserve	$ 44,959	44,334
Number of operating segments \| segment	1
Number of reportable segments \| segment	1
Number of merchandise categories \| merchandise_category	3
Fuel \| Retail Sales
Concentration Risk
Concentration risk percentage	60.00%
Grocery and other merchandise \| Retail Sales
Concentration Risk
Concentration risk percentage	28.00%
Prepared food and fountain \| Retail Sales
Concentration Risk
Concentration risk percentage	12.00%
Accounting Standards Update 2014-09 \| GIft Cards
Concentration Risk
Shareholders' equity				$ 879
Deferred income taxes				321
Accounting Standards Update 2014-09 \| Box Tops
Concentration Risk
Shareholders' equity				(5,019)
Deferred income taxes				$ (1,816)
Capitalized software costs
Concentration Risk
Finite-lived intangible assets	$ 38,593	$ 27,873
Capitalized software costs \| Minimum
Concentration Risk
Intangible asset useful life	3 years
Capitalized software costs \| Maximum
Concentration Risk
Intangible asset useful life	13 years