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Stock Compensation Plans - Summary of Espp Share Activity (Detail) | 12 Months Ended
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Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Available for future purchases, December 31, 2014 | 2,632,628 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
2009 Employee Stock Purchase Plan [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Available for future purchases, January 1, 2014 | 327,689 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardTypeAxis = lamr_TwoThousandNineEmployeeStockPurchasePlanMember
Additional shares reserved under 2009 ESPP | 80,209 lamr_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalNumberOfSharesReservedForAvailableForIssuance / us-gaap_AwardTypeAxis = lamr_TwoThousandNineEmployeeStockPurchasePlanMember
Purchases | (100,450)us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans / us-gaap_AwardTypeAxis = lamr_TwoThousandNineEmployeeStockPurchasePlanMember
Available for future purchases, December 31, 2014 | 307,448 us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant / us-gaap_AwardTypeAxis = lamr_TwoThousandNineEmployeeStockPurchasePlanMember

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- Definition Share based compensation arrangement by share based payment award additional number of shares reserved for available for issuance. + References No definition available. + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Number of shares issued during the period as a result of an employee stock purchase plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 + Details
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