Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 01, 2018
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Trading Symbol	LAMR
Entity Registrant Name	LAMAR ADVERTISING CO/NEW
Entity Central Index Key	0001090425
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Common Class A [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		85,085,392
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		14,420,085
LAMAR MEDIA CORP. AND SUBSIDIARIES [Member]
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Entity Registrant Name	LAMAR MEDIA CORP/DE
Entity Central Index Key	0000899045
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
LAMAR MEDIA CORP. AND SUBSIDIARIES [Member] | Class Units [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		100