Segment Data (Schedule of Segment Reporting Information) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 513,659	$ 507,547	$ 500,147	$ 493,292	$ 483,849	$ 467,221	$ 456,322	$ 458,303	$ 2,014,645	$ 1,865,695	$ 1,727,674
Cost of revenues									493,031	468,795	446,312
Operating profit									1,521,614	1,396,900	1,281,362
Selling, general, and administrative expenses									192,717	142,526	130,697
Acquisition and new business initiatives related adjustments and expenses									15,228	10,961	12,367
Asset impairment and decommission costs									33,103	27,134	36,697
Depreciation, amortization and accretion	179,487	174,987	171,564	171,040	169,454	167,703	169,558	165,398	697,078	672,113	643,100
Operating income	153,920	$ 153,847	$ 136,452	$ 139,269	150,321	$ 138,006	$ 125,870	$ 129,969	583,488	544,166	458,501
Other expense (principally interest expense and other income (expense))									(396,599)	(492,482)	(341,610)
Income before income taxes									186,889	51,684	116,891
Cash capital expenditures									931,692	602,680	588,845
Assets	9,759,941				7,213,707				9,759,941	7,213,707
Domestic Site Leasing [Member]
Segment Reporting Information [Line Items]
Revenues									1,487,108	1,400,095	1,308,389
Cost of revenues									258,413	266,131	260,826
Operating profit									1,228,695	1,133,964	1,047,563
Selling, general, and administrative expenses									99,707	72,879	67,263
Acquisition and new business initiatives related adjustments and expenses									7,933	5,268	8,171
Asset impairment and decommission costs									24,202	18,857	29,523
Depreciation, amortization and accretion									527,718	511,823	498,842
Operating income									569,135	525,137	443,764
Cash capital expenditures									287,793	338,610	225,074
Assets	6,157,511				5,035,826				6,157,511	5,035,826
International Site Leasing [Member]
Segment Reporting Information [Line Items]
Revenues									373,750	340,339	314,784
Cost of revenues									115,538	106,165	98,701
Operating profit									258,212	234,174	216,083
Selling, general, and administrative expenses									32,411	27,082	24,320
Acquisition and new business initiatives related adjustments and expenses									7,295	5,693	4,196
Asset impairment and decommission costs									8,899	7,932	6,994
Depreciation, amortization and accretion									161,183	151,570	135,155
Operating income									48,424	41,897	45,418
Cash capital expenditures									635,728	258,785	358,691
Assets	3,381,448				2,042,800				3,381,448	2,042,800
Site Development [Member]
Segment Reporting Information [Line Items]
Revenues									153,787	125,261	104,501
Cost of revenues									119,080	96,499	86,785
Operating profit									34,707	28,762	17,716
Selling, general, and administrative expenses									21,525	16,215	15,433
Asset impairment and decommission costs									2	345	180
Depreciation, amortization and accretion									2,341	2,556	2,580
Operating income									10,839	9,646	(477)
Cash capital expenditures									3,900	1,561	1,221
Assets	81,772				60,775				81,772	60,775
Not Identified by Segment [Member]
Segment Reporting Information [Line Items]
Selling, general, and administrative expenses									39,074	26,350	23,681
Depreciation, amortization and accretion									5,836	6,164	6,523
Operating income									(44,910)	(32,514)	(30,204)
Other expense (principally interest expense and other income (expense))									(396,599)	(492,482)	(341,610)
Cash capital expenditures									4,271	3,724	$ 3,859
Assets	$ 139,210				$ 74,306				$ 139,210	$ 74,306