Schedule III - Summary of Compnay's Real Estate Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Gross real estate assets:
Balance at the beginning of the year	$ 2,459,425us-gaap_RealEstateGrossAtCarryingValue	$ 2,378,940us-gaap_RealEstateGrossAtCarryingValue
Additions for construction, acquisition, improvements to structures	98,857us-gaap_RealEstateImprovements	112,459us-gaap_RealEstateImprovements
Assets sold or written-off	(36,392)us-gaap_RealEstateCostOfRealEstateSold	(31,328)us-gaap_RealEstateCostOfRealEstateSold
Foreign exchange	(1,246)lamr_RealEstateForeignExchange	(646)lamr_RealEstateForeignExchange
Balance at the end of the year	2,520,644us-gaap_RealEstateGrossAtCarryingValue	2,459,425us-gaap_RealEstateGrossAtCarryingValue
Accumulated depreciation:
Balance at the beginning of the year	1,799,325	1,657,784
Depreciation	135,679	161,172
Assets sold or written-off	(30,994)	(19,213)
Foreign exchange	(576)	(418)
Balance at the end of the year	1,903,434	1,799,325
LAMAR MEDIA CORP [Member]
Gross real estate assets:
Balance at the beginning of the year	2,459,425	2,378,940
Additions for construction, acquisition, improvements to structures	98,857	112,459
Assets sold or written-off	(36,392)	(31,328)
Foreign exchange	(1,246)	(646)
Balance at the end of the year	2,520,644	2,459,425
Accumulated depreciation:
Balance at the beginning of the year	1,799,325	1,657,784
Depreciation	135,679	161,172
Assets sold or written-off	(30,994)	(19,213)
Foreign exchange	(576)	(418)
Balance at the end of the year	$ 1,903,434	$ 1,799,325

Real estate accumulated depreciation, foreign exchange.

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Real estate, foreign exchange.

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No definition available.

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- Definition

Amount of accumulated depreciation pertaining to real estate investments for entities with a substantial portion of business acquiring and holding investment real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 970

-SubTopic 360

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-28.FN4)

-URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section S99

-Paragraph 6

-Subparagraph (SX 210.5-04.(c) Schedule III)

-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 28

-Article 12

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph c

-Subparagraph Schedule III

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Amount of decrease to accumulated depreciation for real estate investments sold for entities with a substantial portion of business acquiring and holding investment real estate.

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Amount of real estate investments sold for entities with a substantial portion of business acquiring and holding investment real estate.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section S99

-Paragraph 6

-Subparagraph (SX 210.5-04.(c) Schedule III)

-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 970

-SubTopic 360

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-28.4)

-URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024

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Amount, before accumulated depreciation, of real estate investments for entities with a substantial portion of business acquiring and holding investment real estate.

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Amount of increase in real estate investments related to improvements for entities with a substantial portion of business acquiring and holding investment real estate.

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Amount of depreciation expense of real estate investments for entities with a substantial portion of business acquiring and holding investment real estate.

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