Document And Entity Information - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Jun. 30, 2019	Aug. 01, 2019	Dec. 31, 2018
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)		27,492
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Current Fiscal Year End Date	--06-30
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Public Float			$ 3,315.5
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	Yes