Cash portion of gains losses on extinguishment of debt.

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Percentage premium which may be required for repayment if the Company undergoes a change in control.

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No definition available.

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Line of credit facility additional revolving commitment.

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No definition available.

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Line of credit facility amended and restated date.

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Ratio of indebtedness to net capital minimum.

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No definition available.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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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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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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No definition available.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

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The cash inflow from bank borrowing during the year.

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The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

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Indebtedness divided by net capital.

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No definition available.

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Long-term Debt - Additional Information (Detail)										9 Months Ended
Long-term Debt - Additional Information (Detail)	Feb. 01, 2019 USD ($)	Dec. 18, 2018 USD ($)	Mar. 19, 2018	Mar. 16, 2018 USD ($)	May 15, 2017 USD ($)	Jan. 28, 2016 USD ($)	Jan. 10, 2014 USD ($)	Oct. 30, 2012 USD ($)	Feb. 09, 2012 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Jan. 17, 2019 USD ($)	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Proceeds received from term A loans											$ 599,250,000
Additional revolving commitment												$ 100,000,000
Outstanding revolving credit facility										$ 215,000,000
Remaining borrowing capacity under revolving credit facility										322,148,000
Aggregate principal amount of debt issued										3,079,710,000
Debt instrument outstanding amount										3,079,710,000			$ 2,914,552,000
Loss on debt extinguishment											15,429,000
AR Program [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Dec. 17, 2021
Aggregate principal amount of debt issued		$ 175,000,000
Debt instrument outstanding amount										$ 175,000,000
Bearing interest rate										3.80%
5 7/8% Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Redemption price, percentage of loan			101.958%
Aggregate principal amount of debt issued									$ 500,000,000
Interest rate on convertible notes									5.875%
Net proceeds from the issuance of debt									$ 489,000,000
Loss on debt extinguishment											15,429,000
Loss on debt extinguishment on cash											9,790,000
5% Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount of debt issued								$ 535,000,000
Debt instrument outstanding amount										$ 535,000,000			$ 535,000,000
Interest rate on convertible notes								5.00%		5.00%			5.00%
Net proceeds from the issuance of debt								$ 527,100,000
Redemption price percentage of the principal amount to be purchased								101.00%
5 3/8% Senior Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount of debt issued							$ 510,000,000
Debt instrument outstanding amount										$ 510,000,000			$ 510,000,000
Interest rate on convertible notes							5.375%			5.375%			5.375%
Net proceeds from the issuance of debt							$ 502,300,000
Redemption price percentage of the principal amount to be purchased							101.00%
5 3/4% Senior Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount of debt issued						$ 400,000,000
Debt instrument outstanding amount										$ 654,524,000			$ 400,000,000
Interest rate on convertible notes						5.75%				5.75%			5.75%
Net proceeds from the issuance of debt						$ 394,500,000
Redemption price percentage of the principal amount to be purchased	101.00%
5 3/4% Senior Notes [Member] \| Prior to February 1, 2021 [Member]
Debt Instrument [Line Items]
Redemption price, percentage of loan	100.00%
5 3/4% Senior Notes [Member] \| Private Placement [Member]
Debt Instrument [Line Items]
Aggregate principal amount of debt issued	$ 250,000,000
Interest rate on convertible notes	5.75%
Net proceeds from the issuance of debt	$ 251,500,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Letter of credit outstanding balance										$ 12,852,000
LAMAR MEDIA CORP. AND SUBSIDIARIES [Member]
Debt Instrument [Line Items]
Proceeds received from term A loans											599,250,000
Loss on debt extinguishment											$ 15,429,000
Senior Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing limit of incremental loan facility					$ 450,000,000
Debt instrument maturity date					May 15, 2022
Term A Loan Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing limit of incremental loan facility					$ 450,000,000
Debt instrument maturity date					May 15, 2022
Proceeds received from term A loans					$ 450,000,000
Term A Loan Facility [Member] \| LIBO Rate [Member]
Debt Instrument [Line Items]
Adjusted Rate				1.75%
Ratio of indebtedness to net capital one				3.25
Ratio of indebtedness to net capital minimum				1
Term A Loan Facility [Member] \| LIBO Rate [Member] \| Debt Ratio Less Than Three Point Two Five [Member]
Debt Instrument [Line Items]
Adjusted Rate				1.50%
Term A Loan Facility [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Adjusted Rate				0.75%
Ratio of indebtedness to net capital one				3.25
Ratio of indebtedness to net capital minimum				1
Term A Loan Facility [Member] \| Base Rate [Member] \| Debt Ratio Less Than Three Point Two Five [Member]
Debt Instrument [Line Items]
Adjusted Rate				0.50%
Term B Loan Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing limit of incremental loan facility				$ 600,000,000
Debt instrument maturity date				Mar. 16, 2025
Amended and restated date				Mar. 16, 2018
Redemption price, percentage of loan				5.875%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing limit of incremental loan facility												$ 550,000,000
Revolving Credit Facility [Member] \| LAMAR MEDIA CORP. AND SUBSIDIARIES [Member]
Debt Instrument [Line Items]
Debt instrument maturity date										May 15, 2022
Revolving Credit Facility [Member] \| LIBO Rate [Member]
Debt Instrument [Line Items]
Adjusted Rate				2.25%
Ratio of indebtedness to net capital one				4.25
Ratio of indebtedness to net capital minimum				1
Revolving Credit Facility [Member] \| LIBO Rate [Member] \| Debt Ratio Less Than Four Point Two Five [Member]
Debt Instrument [Line Items]
Adjusted Rate				2.00%
Revolving Credit Facility [Member] \| LIBO Rate [Member] \| Debt Ratio Less Than Three Point Zero Zero [Member]
Debt Instrument [Line Items]
Adjusted Rate				1.75%
Ratio of indebtedness to net capital one				3.00
Ratio of indebtedness to net capital minimum				1
Revolving Credit Facility [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Adjusted Rate				1.25%
Ratio of indebtedness to net capital one				4.25
Ratio of indebtedness to net capital minimum				1
Revolving Credit Facility [Member] \| Base Rate [Member] \| Debt Ratio Less Than Four Point Two Five [Member]
Debt Instrument [Line Items]
Adjusted Rate				1.00%
Revolving Credit Facility [Member] \| Base Rate [Member] \| Debt Ratio Less Than Three Point Zero Zero [Member]
Debt Instrument [Line Items]
Adjusted Rate				0.75%
Ratio of indebtedness to net capital one				3.00
Ratio of indebtedness to net capital minimum				1