Document And Entity Information - USD ($)	12 Months Ended
	Jun. 30, 2016	Aug. 27, 2016	Dec. 31, 2015
Document Information [Line Items]
Entity Registrant Name	LSI INDUSTRIES INC
Entity Central Index Key	0000763532
Trading Symbol	lyts
Current Fiscal Year End Date	--06-30
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Common Stock, Shares Outstanding (in shares)		24,978,016
Entity Public Float			$ 300,176,800
Document Type	10-K
Document Period End Date	Jun. 30, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Amendment Flag	false