Significant Accounting Policies (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Apr. 30, 2013 store state customer	Apr. 30, 2012	Apr. 30, 2011
Significant Accounting Policies [Line Items]
Number of stores	1,749
Number of states in which entity operates	14
Population of communities stores are located within	5,000
Excess of current cost over the stated LIFO value	$ 44,792	$ 41,805
Goodwill	114,791	104,385
Asset impaiment charge	3,680	226	348
Excise taxes colleted from customers on retail gasoline sales	596,000	527,000	495,000
Asset retirement obligation in other assets net of amortization	8,011	7,343
Asset retirement obligation discounted liability recorded in other long-term liabilities	12,176	11,313
Self-insurance reserves	24,039	23,701
Other comprehensive income (loss)	$ 0	$ 0	$ 0
Gasoline [Member]
Significant Accounting Policies [Line Items]
Percentage of sales	72.00%
Grocery And Other Merchandise [Member]
Significant Accounting Policies [Line Items]
Percentage of sales	20.00%
Prepared Food & Fountain [Member]
Significant Accounting Policies [Line Items]
Percentage of sales	8.00%

Asset Retirement Obligation In Other Assets Net Of Amortization.

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Population Of Communities

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The charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value.

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Amount of asset retirement obligations incurred during the period.

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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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Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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The number of states the entity operates in as of the balance sheet date.

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Represents the number of stores.

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Before tax amount of other comprehensive income (loss) attributable to both parent entity and noncontrolling interest.

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The percentage of net product revenue to total net revenue from the sale of goods as of year end.

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Carrying amount (including both current and noncurrent portions) of accrued known and estimated losses incurred as of the balance sheet date for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property.

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