Acquisitions (Narrative) (Details)	12 Months Ended
Apr. 30, 2012 Y
Acquisitions [Abstract]
Number of stores acquired	35
Goodwill deductible for income tax purposes, period (years)	15

Total number of stoes acquired through a variety of single and multi-store transactions.

No definition available.

Name:	casy_NumberOfStoresAcquired
Namespace Prefix:	casy_
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	duration