Valuation and Qualifying Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deducted in balance sheet from trade accounts receivable: Allowance for doubtful accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 7,500	$ 8,100	$ 9,550
Charged to Costs and Expenses	5,484	7,591	8,736
Deductions	5,369	8,191	10,186
Balance at End of Period	7,615	7,500	8,100
Deducted in balance sheet from trade accounts receivable: Allowance for doubtful accounts [Member] | LAMAR MEDIA CORP [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	7,500	8,100	9,550
Charged to Costs and Expenses	5,484	7,591	8,736
Deductions	5,369	8,191	10,186
Balance at End of Period	7,615	7,500	8,100
Deducted in balance sheet from intangible assets: Amortization of intangible assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	1,705,402	1,602,723	1,497,763
Charged to Costs and Expenses	102,941	102,679	104,960
Deductions	13,928
Balance at End of Period	1,794,415	1,705,402	1,602,723
Deducted in balance sheet from intangible assets: Amortization of intangible assets [Member] | LAMAR MEDIA CORP [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	1,704,492	1,601,843	1,496,912
Charged to Costs and Expenses	102,941	102,649	104,931
Deductions	13,957
Balance at End of Period	$ 1,793,476	$ 1,704,492	$ 1,601,843