Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2017	Aug. 03, 2017	Dec. 31, 2016
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Fiscal Period Focus	FY
Entity Central Index Key	0000057515
Entity Registrant Name	LANCASTER COLONY CORP
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)		27,449,235
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2017
Current Fiscal Year End Date	--06-30
Entity Public Float			$ 2,637.6
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	Yes