Debt Instrument Carrying Amount Of Each Note

No definition available.

Name:	casy_DebtInstrumentCarryingAmountOfEachNote
Namespace Prefix:	casy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Interest Over Index

+ References

No definition available.

+ Details

Name:	casy_InterestOverIndex
Namespace Prefix:	casy_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	casy_Note4FairValueofFinancialInstrumentsandLongTermDebtDetailsLineItems
Namespace Prefix:	casy_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of notes.

+ References

No definition available.

+ Details

Name:	casy_NumberOfNotes
Namespace Prefix:	casy_
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of interest capitalized during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Allowance for Funds Used during Construction

-URI http://asc.fasb.org/extlink&oid=6504829

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

+ Details

Name:	us-gaap_InterestCostsCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The net amount of operating interest income (expense).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.10)

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 10

-Article 9

+ Details

Name:	us-gaap_InterestIncomeExpenseNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount borrowed under the credit facility as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityAmountOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of decrease in line of credit facility from forgiveness by the holder of the line of credit.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityDecreaseForgiveness1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Note 4 - Fair Value of Financial Instruments and Long Term Debt (Details) (USD $)	0 Months Ended	12 Months Ended
	Dec. 17, 2013	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2012
Note 4 - Fair Value of Financial Instruments and Long Term Debt (Details) [Line Items]
Long-term Debt, Fair Value		$ 841,000,000	$ 721,000,000
Number Of Notes		2
Line of Credit Facility, Maximum Borrowing Capacity			100,000,000
Line of Credit Facility, Decrease, Forgiveness	25,000,000
Interest Income (Expense), Net		214,000	211,000	208,000
Interest Costs Capitalized		1,177,000	894,000	674,000
Note1 And Note 2 [Member]
Note 4 - Fair Value of Financial Instruments and Long Term Debt (Details) [Line Items]
Debt Instrument Carrying Amount Of Each Note		50,000,000
Note 1 [Member]
Note 4 - Fair Value of Financial Instruments and Long Term Debt (Details) [Line Items]
Interest Over Index		0.75%
Note 2 [Member]
Note 4 - Fair Value of Financial Instruments and Long Term Debt (Details) [Line Items]
Interest Over Index		1.00%
Note 3 [Member]
Note 4 - Fair Value of Financial Instruments and Long Term Debt (Details) [Line Items]
Line of Credit Facility, Amount Outstanding		$ 0	$ 59,100,000