Document And Entity Information	6 Months Ended
	Oct. 31, 2011	Dec. 02, 2011
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Oct. 31, 2011
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2012
Entity Registrant Name	CASEYS GENERAL STORES INC
Entity Central Index Key	0000726958
Current Fiscal Year End Date	--04-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		38,061,659