Condensed Consolidating Statements of Income and Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net revenues	$ 418,498	$ 399,345	$ 1,199,324	$ 1,142,785
Type of Revenue [Extensible List]	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember
Operating expenses
Direct advertising expenses	$ 140,699	$ 134,977	$ 419,776	$ 401,896
Type of Cost, Good or Service [Extensible List]	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember
General and administrative expenses	$ 73,166	$ 68,500	$ 213,060	$ 206,452
Corporate expenses	20,776	15,088	62,027	48,451
Depreciation and amortization	55,089	51,796	167,251	155,003
Loss (gain) on disposition of assets	407	(2,734)	7,265	(4,377)
Total Operating Expenses	290,137	267,627	869,379	807,425
Operating income	128,361	131,718	329,945	335,360
Income before income tax expense	96,668	99,656	217,508	239,769
Income tax expense	2,612	3,325	7,969	9,257
Net income	94,056	96,331	209,539	230,512
Statements of Comprehensive Income
Net income	94,056	96,331	209,539	230,512
Comprehensive income	94,277	97,547	208,940	232,616
LAMAR MEDIA CORP. AND SUBSIDIARIES [Member]
Net revenues	$ 418,498	$ 399,345	$ 1,199,324	$ 1,142,785
Type of Revenue [Extensible List]	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember
Operating expenses
Direct advertising expenses	$ 140,699	$ 134,977	$ 419,776	$ 401,896
Type of Cost, Good or Service [Extensible List]	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember
General and administrative expenses	$ 73,166	$ 68,500	$ 213,060	$ 206,452
Corporate expenses	20,667	14,982	61,723	48,154
Depreciation and amortization	55,089	51,796	167,251	155,003
Loss (gain) on disposition of assets	407	(2,734)	7,265	(4,377)
Total Operating Expenses	290,028	267,521	869,075	807,128
Operating income	128,470	131,824	330,249	335,657
Interest expense (income), net			97,008	95,520
Other expenses (income)	31,693	32,062	15,429	71
Income before income tax expense	96,777	99,762	217,812	240,066
Income tax expense	2,612	3,325	7,969	9,257
Net income	94,165	96,437	209,843	230,809
Statements of Comprehensive Income
Net income	94,165	96,437	209,843	230,809
Total other comprehensive income (loss), net of tax	221	1,216	(599)	2,104
Comprehensive income	$ 94,386	$ 97,653	$ 209,244	$ 232,913
LAMAR MEDIA CORP. AND SUBSIDIARIES [Member] | Reportable Legal Entities [Member] | Lamar Media [Member]
Type of Revenue [Extensible List]	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember
Operating expenses
Type of Cost, Good or Service [Extensible List]	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember
Equity in (earnings) loss of subsidiaries	$ (126,015)	$ (128,500)	$ (322,592)	$ (326,401)
Interest expense (income), net			97,320	95,521
Other expenses (income)	31,850	32,063	15,429	71
Income before income tax expense	94,165	96,437	209,843	230,809
Net income	94,165	96,437	209,843	230,809
Statements of Comprehensive Income
Net income	94,165	96,437	209,843	230,809
Comprehensive income	94,165	96,437	209,843	230,809
LAMAR MEDIA CORP. AND SUBSIDIARIES [Member] | Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Net revenues	$ 407,656	$ 387,095	$ 1,164,039	$ 1,107,583
Type of Revenue [Extensible List]	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember
Operating expenses
Direct advertising expenses	$ 134,863	$ 128,175	$ 400,703	$ 381,317
Type of Cost, Good or Service [Extensible List]	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember
General and administrative expenses	$ 71,046	$ 66,467	$ 206,522	$ 199,979
Corporate expenses	20,252	14,705	60,468	47,320
Depreciation and amortization	53,956	49,475	162,536	148,357
Loss (gain) on disposition of assets	559	(2,737)	(268)	(4,377)
Total Operating Expenses	280,676	256,085	829,961	772,596
Operating income	126,980	131,010	334,078	334,987
Interest expense (income), net			(18)	(5)
Other expenses (income)	(8)	(2)
Income before income tax expense	126,988	131,012	334,096	334,992
Income tax expense	2,167	2,659	5,708	7,528
Net income	124,821	128,353	328,388	327,464
Statements of Comprehensive Income
Net income	124,821	128,353	328,388	327,464
Comprehensive income	124,821	128,353	328,388	327,464
LAMAR MEDIA CORP. AND SUBSIDIARIES [Member] | Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Net revenues	$ 11,659	$ 13,303	$ 37,880	$ 38,191
Type of Revenue [Extensible List]	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember
Operating expenses
Direct advertising expenses	$ 6,522	$ 7,408	$ 21,042	$ 22,330
Type of Cost, Good or Service [Extensible List]	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember
General and administrative expenses	$ 2,120	$ 2,033	$ 6,538	$ 6,473
Corporate expenses	415	277	1,255	834
Depreciation and amortization	1,133	2,321	4,715	6,646
Loss (gain) on disposition of assets	(152)	3	7,533
Total Operating Expenses	10,038	12,042	41,083	36,283
Operating income	1,621	1,261	(3,203)	1,908
Interest expense (income), net			332	1,242
Other expenses (income)	(18)	448
Income before income tax expense	1,639	813	(3,535)	666
Income tax expense	445	666	2,261	1,729
Net income	1,194	147	(5,796)	(1,063)
Statements of Comprehensive Income
Net income	1,194	147	(5,796)	(1,063)
Total other comprehensive income (loss), net of tax	221	1,216	(599)	2,104
Comprehensive income	1,415	1,363	(6,395)	1,041
LAMAR MEDIA CORP. AND SUBSIDIARIES [Member] | Eliminations [Member]
Net revenues	$ (817)	$ (1,053)	$ (2,595)	$ (2,989)
Type of Revenue [Extensible List]	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember
Operating expenses
Direct advertising expenses	$ (686)	$ (606)	$ (1,969)	$ (1,751)
Type of Cost, Good or Service [Extensible List]	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember	us-gaap:AdvertisingMember
Total Operating Expenses	$ (686)	$ (606)	$ (1,969)	$ (1,751)
Operating income	(131)	(447)	(626)	(1,238)
Equity in (earnings) loss of subsidiaries	126,015	128,500	322,592	326,401
Interest expense (income), net			(626)	(1,238)
Other expenses (income)	(131)	(447)
Income before income tax expense	(126,015)	(128,500)	(322,592)	(326,401)
Net income	(126,015)	(128,500)	(322,592)	(326,401)
Statements of Comprehensive Income
Net income	(126,015)	(128,500)	(322,592)	(326,401)
Comprehensive income	$ (126,015)	$ (128,500)	$ (322,592)	$ (326,401)