Segment Data (Segment Reporting Information Disclosure) (Details) (USD $) In Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010		Dec. 31, 2010
Revenues	$ 171,053		$ 154,515		$ 338,802		$ 302,480
Cost of revenues	50,107	[1]	49,958	[1]	100,811	[1]	97,030	[1]
Depreciation, amortization and accretion	76,691		68,831		151,569		136,277
Operating income (loss)	27,209		20,024		51,108		36,910
Capital expenditures	111,679	[2]	97,144	[2]	222,369	[2]	139,888	[2]
Assets	3,693,009				3,693,009				3,400,175
Site Leasing [Member]
Revenues	150,173		131,739		296,657		259,706
Cost of revenues	32,123	[1]	30,004	[1]	64,099	[1]	59,187	[1]
Depreciation, amortization and accretion	76,048		68,314		150,313		135,277
Operating income (loss)	28,477		21,300		53,512		40,004
Capital expenditures	110,394	[2]	96,668	[2]	220,046	[2]	138,686	[2]
Assets	3,299,772				3,299,772				3,218,892
Site Development Consulting [Member]
Revenues	4,672		4,680		8,863		9,263
Cost of revenues	3,540	[1]	3,649	[1]	6,767	[1]	7,281	[1]
Depreciation, amortization and accretion	49		45		94		93
Operating income (loss)	679		622		1,250		1,127
Capital expenditures	66	[2]	24	[2]	107	[2]	105	[2]
Assets	4,035				4,035				4,458
Site Development Construction [Member]
Revenues	16,208		18,096		33,282		33,511
Cost of revenues	14,444	[1]	16,305	[1]	29,945	[1]	30,562	[1]
Depreciation, amortization and accretion	310		261		620		490
Operating income (loss)	47		113		(107)		(298)
Capital expenditures	392	[2]	332	[2]	757	[2]	655	[2]
Assets	31,823				31,823				35,567
Not Identified by Segment [Member]
Revenues				[3]		[3]		[3]
Cost of revenues		[1],[3]		[1],[3]		[1],[3]		[1],[3]
Depreciation, amortization and accretion	284	[3]	211	[3]	542	[3]	417	[3]
Operating income (loss)	(1,994)	[3]	(2,011)	[3]	(3,547)	[3]	(3,923)	[3]
Capital expenditures	827	[2],[3]	120	[2],[3]	1,459	[2],[3]	442	[2],[3]
Assets	$ 357,379	[3]			$ 357,379	[3]			$ 141,258	[3]

[1] Excludes depreciation, amortization and accretion.

[2] Includes cash paid for capital expenditures and acquisitions and related earn-outs and vehicle capital lease additions.

[3] Assets not identified by segment consist primarily of general corporate assets.