Significant Accounting Policies (Details) people in Thousands, $ in Thousands	12 Months Ended
Apr. 30, 2015 USD ($) people state segment store	Apr. 30, 2014 USD ($) merchandise_category	Apr. 30, 2013 USD ($)
Accounting Policies [Abstract]
Number of stores \| store	1,878
Number of states in which entity operates \| state	14
Population of communities (many less than) \| people	5
Concentration Risk
Excess of current cost over the stated LIFO Value	$ 53,428	$ 48,777
Goodwill	127,046	120,406
Asset impairment charges	1,785	2,542	$ 3,680
Recorded asset retirement obligation (net of amortization)	9,234	8,391
Discounted liability of asset retirement obligation	14,014	12,854
Self-insurance reserves	$ 31,389	$ 28,429
Number of operating segments \| segment	1
Number of reportable segments \| segment	1
Number of merchandise categories \| merchandise_category		3
Fuel
Concentration Risk
Excise taxes collected	$ 715,000	$ 646,000	$ 596,000
Fuel \| Retail Sales
Concentration Risk
Concentration risk percentage	66.00%
Grocery & Other Merchandise \| Retail Sales
Concentration Risk
Concentration risk percentage	24.00%
Prepared Food & Fountain \| Retail Sales
Concentration Risk
Concentration risk percentage	10.00%

Accrued Expenses For Estimated Claims Relating To Self Insurance

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The recorded asset for asset retirement obligations is recorded in other assets,net of amortization.

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Population of Communities

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Segment Reporting, Number of Merchandise Categories

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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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The excess of replacement or current cost over the stated LIFO (last in first out) inventory value when the LIFO inventory method is utilized.

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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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Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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Represents the number of stores.

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