Segment Data (Segment Reporting Information Disclosure) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]
Revenues	$ 335,396		$ 332,094	$ 324,305	$ 313,071	$ 293,841		$ 238,606	$ 229,147	$ 192,490	$ 1,304,866		$ 954,084		$ 698,170
Cost of revenues											408,253	[1]	279,507	[1]	202,921	[1]
Depreciation, amortization and accretion	133,328		133,281	141,089	125,636	131,357		101,012	93,998	82,100	533,334		408,467		309,146
Operating income (loss)	59,445		63,902	49,534	56,764	31,048		41,071	34,738	40,289	229,645		147,146		110,659
Capital expenditures											856,835	[2]	2,374,429	[2]	508,828	[2]
Assets	6,783,188					6,615,911					6,783,188		6,615,911
Site Leasing Revenue [Member]
Segment Reporting Information [Line Items]
Revenues											1,133,013		846,094		616,294
Cost of revenues											270,772	[1]	188,951	[1]	131,916	[1]
Depreciation, amortization and accretion											529,026		404,976		306,386
Operating income (loss)											215,672		149,642		116,681
Capital expenditures											850,037	[2]	2,364,212	[2]	502,222	[2]
Assets	6,468,370					6,422,577					6,468,370		6,422,577
Site Development [Member]
Segment Reporting Information [Line Items]
Revenues											171,853		107,990		81,876
Cost of revenues											137,481	[1]	90,556	[1]	71,005	[1]
Depreciation, amortization and accretion											2,280		2,118		1,583
Operating income (loss)											24,332		7,129		2,077
Capital expenditures											6,693	[2]	6,466	[2]	3,935	[2]
Assets	76,214					58,804					76,214		58,804
Not Identified by Segment [Member]
Segment Reporting Information [Line Items]
Depreciation, amortization and accretion											2,028	[3]	1,373	[3]	1,177	[3]
Operating income (loss)											(10,359)	[3]	(9,625)	[3]	(8,099)	[3]
Capital expenditures											105	[2],[3]	3,751	[2],[3]	2,671	[2],[3]
Assets	$ 238,604	[3]				$ 134,530	[3]				$ 238,604	[3]	$ 134,530	[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.