Common stock dividends per share cash paid declared in prior period.

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Investment maturity period.

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- Definition

Number of Advertising displays as of the balance sheet date.

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- Definition

Number of states in which the entity operates with logo sign business as of the balance sheet date.

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- Definition

Number of states in which entity operates with transit advertising business.

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Number of transit advertising displays.

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- Definition

Payment of dividends declared in prior period.

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No definition available.

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Percentage net income available for dividend distribution.

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- Definition

Preferred stock dividends declared

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No definition available.

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Aggregate dividends paid during the period for each share of common stock outstanding.

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- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment.

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The number of states the entity operates in as of the balance sheet date.

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Cash outflow in the form of capital distributions and dividends to common shareholders, preferred shareholders and noncontrolling interests.

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Amount of cash outflow in the form of ordinary dividends to preferred shareholders of the parent entity.

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Aggregate dividends paid during the period for each share of preferred stock outstanding.

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Aggregate dividends declared during the period for each share of preferred stock outstanding.

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Amount of noncash expense for share-based payment arrangement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Significant Accounting Policies- Additional Information (Detail) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021 USD ($) $ / shares shares	Mar. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) State Billboard Reporting_Unit Transit $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of advertising displays \| Billboard			153,200
Number of states in which the company operates \| State			45
Number of states in which the company operates logo sign business \| State			23
Number of transit advertising displays \| Transit			47,700
Number of states in which the company operates transit advertising displays \| State			22
Number of reporting units \| Reporting_Unit			2
REIT threshold percentage of taxable income to be distributed to stockholders			90.00%
Dividends paid in current year declared in prior period					$ 81,534
Dividends paid in current year declared in prior period, per share \| $ / shares					$ 0.83
Distributions paid	$ 75,818	$ 100,687
Distributions paid, per share \| $ / shares	$ 0.75	$ 1.00
Distributions accrued, preferred stockholders						$ 91
Distributions accrued, preferred stockholders, per share \| $ / shares						$ 15.95
Distributions paid, preferred stockholders			$ 365	$ 365	$ 456
Distributions paid, preferred stockholders, per share \| $ / shares	$ 15.95	$ 15.95	$ 63.80	$ 63.80	$ 79.75
The number of dilutive shares excluded from calculation of basic earnings per share resulting from the anti-dilutive effect for stock options \| shares	0	0	0	0	0
Non cash compensation expense	$ 3,675	$ 3,437	$ 18,772	$ 29,647	$ 29,443
Investment maturity period			three months or less
LAMAR MEDIA CORP. AND SUBSIDIARIES [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of advertising displays \| Billboard			153,200
Number of states in which the company operates \| State			45
Number of states in which the company operates logo sign business \| State			23
Non cash compensation expense	$ 3,675	$ 3,437	$ 18,772	29,647	29,443
Stock Options and Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non cash compensation expense			4,249
Performance-Based Stock Incentive Program [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non cash compensation expense			12,602
Non-Performance Restricted Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non cash compensation expense			1,451
Restricted Stock Awards to Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non cash compensation expense			470
Taxable Income Distribution [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Distributions paid			$ 251,944	$ 384,817	$ 442,632
Distributions paid, per share \| $ / shares			$ 2.50	$ 3.84	$ 4.48
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Estimated useful lives of Intangible assets			2 years
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Estimated useful lives of Intangible assets			15 years