Summarized Financial Information of Subsidiaries - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Mar. 27, 2009
Debt Instrument [Line Items]
Balance of permitted transfers to parent company	$ 1,973,528	$ 1,706,875
Description of provisions on senior credit facility transfers to Lamar Advertising subject to additional restrictions	The total holdings debt ratio is greater than 5.75 to 1 or (y) the senior debt ratio is greater than 3.25 to 1.0, and (ii) if under the indenture for Lamar Media's 9 3/4% senior notes and as defined therein, its senior leverage ratio is greater than or equal to 3.0 to 1.
Description of actual position on senior credit facility transfers to Lamar Advertising not subject to additional restrictions	The total holdings debt ratio was less than 5.75 to 1 and Lamar Media's senior debt ratio was less than 3.25 to 1 and its senior leverage ratio was less than 3.0 to 1; therefore, transfers to Lamar Advertising were not subject to any additional restrictions under the senior credit facility or pursuant to the indenture governing the 9 3/4% senior notes.
Holdings debt ratio	5.75
Senior debt ratio	3.25
Senior leverage ratio	3.0
Holdings debt ratio related to actual position on senior credit facility	5.75
Senior leverage ratio related to actual position on senior credit facility	3.0
9 3/4% Senior Notes [Member]
Debt Instrument [Line Items]
Interest rate stated on notes	9.75%	9.75%	9.75%
Minimum [Member]
Debt Instrument [Line Items]
Senior debt ratio	3.25
Maximum [Member]
Debt Instrument [Line Items]
Senior debt ratio	3.25