Quarterly Financial Information (Details) - USD ($) $ in Thousands		3 Months Ended																6 Months Ended				9 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		Jun. 30, 2019		Jun. 30, 2018		Sep. 30, 2019		Sep. 30, 2018		Dec. 31, 2019	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016
Cash and cash equivalents		$ 20,407		$ 18,486		$ 17,679		$ 17,710		$ 18,707		$ 24,236		$ 21,655		$ 28,488		$ 17,679		$ 21,655		$ 18,486		$ 24,236		$ 20,407	$ 18,707		$ 30,771	$ 19,550
Revenues		184,864	[1]	185,181		180,953		179,493		179,306		175,954		174,660		173,061		360,446		347,721		545,627		523,675		730,491	702,981		655,332
Operating income (loss)		69,803	[1]	71,403		67,394		67,708		67,275		64,284		62,491		61,561		135,102		124,052		206,505		188,336		276,308	255,611		214,022
Costs and Expenses				113,778		113,559		111,785		112,031		111,670		112,169		111,500		225,344		223,669		339,122		335,339		454,183	447,370		441,310
Benefit (provision) for income taxes		(119)	[1]	(102)		(107)		(98)		(137)		(93)		(93)		(93)		(205)		(186)		(307)		(279)		(426)	(416)		614
Interest expense and amortization of deferred financing costs																										39,874	39,874		39,874
Net income (loss)		59,940	[1]	61,492		57,607		57,638		57,303		54,312		52,470		51,432		115,245		103,902		176,737		158,214		236,677	215,517		175,049
Receivables, net of allowance of $1,631 and $1,601, respectively		3,620		2,348		1,730		2,811		4,327		2,740		2,350		2,744		1,730		2,350		2,348		2,740		3,620	4,327
Prepaid expenses(a)	[2]	29,643		14,883		18,186		11,569		23,155		28,615		27,444		19,305		18,186		27,444		14,883		28,615		29,643	23,155
Other current assets		564		28,413		29,793		28,917		554		25,739		39,928		29,478		29,793		39,928		28,413		25,739		564	554
Assets, Current		66,948		64,130		67,388		61,007		73,203		81,330		91,377		80,015		67,388		91,377		64,130		81,330		66,948	73,203
Deferred site rental receivables		354,075		352,984		348,047		345,000		343,740		341,633		325,070		331,907		348,047		325,070		352,984		341,633		354,075	343,740
Property and equipment, net		1,010,367		1,008,702		1,008,991		1,005,579		1,010,451		1,014,028		1,017,638		1,024,460		1,008,991		1,017,638		1,008,702		1,014,028		1,010,367	1,010,451
Operating Lease, Right-of-Use Asset	[2]	1,150,476		1,135,264		1,104,505		1,094,798		0								1,104,505				1,135,264				1,150,476	0
Goodwill		1,338,730		1,338,730		1,338,730		1,338,730		1,338,730		1,338,730		1,338,730		1,338,730		1,338,730		1,338,730		1,338,730		1,338,730		1,338,730	1,338,730
Site rental contracts and tenant relationships, net		676,398		707,376	[2]	735,797	[2]	764,217	[2]	789,974		836,156	[2]	864,946	[2]	893,735	[2]	735,797	[2]	864,946	[2]	707,376	[2]	836,156	[2]	676,398	789,974
Other intangible assets, net(a)	[2]	2,558								18,353																2,558	18,353
Long-term prepaid rent and other assets, net(a)		1,905		1,878	[2]	1,930	[2]	2,177	[2]	39,669		39,252	[2]	38,999	[2]	38,789	[2]	1,930	[2]	38,999	[2]	1,878	[2]	39,252	[2]	1,905	39,669
Assets		4,601,457		4,609,064		4,605,388		4,611,508		3,614,120		3,651,129		3,676,760		3,707,636		4,605,388		3,676,760		4,609,064		3,651,129		4,601,457	3,614,120
Accounts payable		2,652		2,164		6,404		1,601		1,933		2,325		2,443		1,738		6,404		2,443		2,164		2,325		2,652	1,933
Accrued interest		8,126		17,748		8,126		17,748		8,126		17,748		8,126		17,748		8,126		8,126		17,748		17,748		8,126	8,126
Deferred revenues		70,217		66,933	[3]	63,973	[3]	61,770	[3]	59,766	[2]	57,765	[3]	54,945	[3]	52,855	[3]	63,973	[3]	54,945	[3]	66,933	[3]	57,765	[3]	70,217	59,766	[2]
Other accrued liabilities(a)		6,146		7,484	[2]	7,722	[2]	10,409	[2]	8,866		8,835	[2]	9,584	[2]	12,589	[2]	7,722	[2]	9,584	[2]	7,484	[2]	8,835	[2]	6,146	8,866
Current portion of operating lease liabilities, third party	[2]	37,164		38,176		35,512		37,662		0								35,512				38,176				37,164	0
Current portion of operating lease liabilities, related party	[2]	20,417		16,397		16,137		18,072		0								16,137				16,397				20,417	0
Liabilities, Current		144,722		148,902		137,874		147,262		78,691		86,673		75,098		84,930		137,874		75,098		148,902		86,673		144,722	78,691
Debt		995,431		995,085		994,739		994,393		994,047		993,701		993,355		993,009		994,739		993,355		995,085		993,701		995,431	994,047
Operating lease liabilities, third party	[2]	845,960		827,253		804,386		795,388		0								804,386				827,253				845,960	0
Member's equity		2,096,954		2,117,704		2,156,857		2,171,364		2,219,198		2,251,629		2,292,123		2,314,516		2,156,857		2,292,123		2,117,704		2,251,629		2,096,954	2,219,198
Operating lease liabilities, related party	[2]	314,920		319,472		314,291		309,975		0								314,291				319,472				314,920	0
Accumulated earnings (deficit)		0		0		0		0		0		0		0		0		0		0		0		0		0	0
Members' Equity		2,096,954		2,117,704		2,156,857		2,171,364		2,219,198		2,251,629		2,292,123		2,314,516		2,156,857		2,292,123		2,117,704		2,251,629		2,096,954	2,219,198		2,371,657	2,531,642
Other long-term liabilities(a)	[2]	203,470		200,648	[3]	197,241	[3]	193,126	[3]	209,352		207,270	[3]	205,835	[3]	206,141	[3]	197,241	[3]	205,835	[3]	200,648	[3]	207,270	[3]	203,470	209,352
Liabilities		2,504,503		2,491,360		2,448,531		2,440,144		1,394,922		1,399,500		1,384,637		1,393,120		2,448,531		1,384,637		2,491,360		1,399,500		2,504,503	1,394,922
Liabilities and Equity		$ 4,601,457		4,609,064		4,605,388		4,611,508		3,614,120		3,651,129		3,676,760		3,707,636		4,605,388		3,676,760		4,609,064		3,651,129		$ 4,601,457	3,614,120
Deferred Rent Credit, Noncurrent												111,856		110,349		109,040				110,349				111,856
Previously Reported [Member]
Cash and cash equivalents				18,486		17,679		17,710		18,707		24,236		21,655		28,488		17,679		21,655		18,486		24,236			18,707		30,771	19,550
Revenues				171,745		168,189		167,322		167,332		165,108		164,056		162,994		335,511		327,050		507,256		492,158			659,490		616,897
Operating income (loss)				57,183		53,847		54,755		54,701		52,789		51,239		50,847		108,602		102,086		165,785		154,875			209,576		172,744
Costs and Expenses				114,562		114,342		112,567		112,631		112,319		112,817		112,147		226,909		224,964		341,471		337,283			449,914		444,153
Net income (loss)				47,272		44,060		44,685		44,729		42,817		41,218		40,718		88,745		81,936		136,017		124,753			169,482		133,771
Property and equipment, net				1,015,632		1,016,024		1,012,769		1,017,767		1,021,517		1,025,250		1,032,214		1,016,024		1,025,250		1,015,632		1,021,517			1,017,767
Assets				4,615,994		4,612,421		4,618,698		3,621,436		3,658,618		3,684,372		3,715,390		4,612,421		3,684,372		4,615,994		3,658,618			3,621,436
Deferred revenues				13,390	[3]	12,347	[3]	12,436	[3]	12,533	[2]	11,709	[3]	12,043	[3]	11,929	[3]	12,347	[3]	12,043	[3]	13,390	[3]	11,709	[3]		12,533	[2]
Liabilities, Current				95,359		86,248		97,928		31,458		40,617		32,196		44,004		86,248		32,196		95,359		40,617			31,458
Member's equity				2,343,207		2,377,756		2,386,672				2,462,508		2,498,784		2,519,881		2,377,756		2,498,784		2,343,207		2,462,508
Members' Equity				2,343,207		2,377,756		2,386,672		2,432,991		2,462,508		2,498,784		2,519,881		2,377,756		2,498,784		2,343,207		2,462,508			2,432,991		2,576,471	2,739,245
Other long-term liabilities(a)	[2]			35,618		35,001		34,342		50,108		49,936		49,688		49,456		35,001		49,688		35,618		49,936			50,108
Liabilities				2,272,787		2,234,665		2,232,026		1,188,445		1,196,110		1,185,588		1,195,509		2,234,665		1,185,588		2,272,787		1,196,110			1,188,445
Liabilities and Equity				4,615,994		4,612,421		4,618,698		3,621,436		3,658,618		3,684,372		3,715,390		4,612,421		3,684,372		4,615,994		3,658,618			3,621,436
Restatement Adjustment [Member]
Cash and cash equivalents				0		0		0		0		0		0		0		0		0		0		0			0		0	0
Revenues				13,436		12,764		12,171		11,974		10,846		10,604		10,067		24,935		20,671		38,371		31,517			43,491		38,435
Operating income (loss)				14,172		13,500		12,907		12,529		11,450		11,208		10,671		26,407		21,879		40,579		33,329			45,858		41,145
Costs and Expenses				(736)		(736)		(736)		(555)		(604)		(604)		(604)		(1,472)		(1,208)		(2,208)		(1,812)			(2,367)		(2,710)
Net income (loss)				14,172		13,500		12,907		12,529		11,450		11,208		10,671		26,407		21,879		40,579		33,329			45,858		41,145
Property and equipment, net				(4,140)		(4,288)		(4,436)		(4,584)		(4,740)		(4,897)		(5,054)		(4,288)		(4,897)		(4,140)		(4,740)			(4,584)
Assets				(4,140)		(4,288)		(4,436)		(4,584)		(4,740)		(4,897)		(5,054)		(4,288)		(4,897)		(4,140)		(4,740)			(4,584)
Deferred revenues				53,543	[3]	51,626	[3]	49,334	[3]	47,233	[2]	46,056	[3]	42,902	[3]	40,926	[3]	51,626	[3]	42,902	[3]	53,543	[3]	46,056	[3]		47,233	[2]
Liabilities, Current				53,543		51,626		49,334		47,233		46,056		42,902		40,926		51,626		42,902		53,543		46,056			47,233
Member's equity				(222,713)		(218,154)		(212,554)				(208,130)		(203,946)		(202,665)		(218,154)		(203,946)		(222,713)		(208,130)
Members' Equity				(222,713)		(218,154)		(212,554)		(211,061)		(208,130)		(203,946)		(202,665)		(218,154)		(203,946)		(222,713)		(208,130)			(211,061)		(202,126)	(206,021)
Other long-term liabilities(a)	[2]			165,030		162,240		158,784		159,244		157,334		156,147		156,685		162,240		156,147		165,030		157,334			159,244
Liabilities				218,573		213,866		208,118		206,477		203,390		199,049		197,611		213,866		199,049		218,573		203,390			206,477
Liabilities and Equity				(4,140)		(4,288)		(4,436)		(4,584)		(4,740)		(4,897)		(5,054)		(4,288)		(4,897)		(4,140)		(4,740)			(4,584)
Other Adjustment [Member]
Cash and cash equivalents				0		0		0		0		0		0		0		0		0		0		0			0		0	0
Revenues				0		0		0		0		0		0		0		0		0		0		0
Operating income (loss)				48		47		46		45		45		44		43		93		87		141		132			177		133
Costs and Expenses				(48)		(47)		(46)		(45)		(45)		(44)		(43)		(93)		(87)		(141)		(132)			(177)		(133)
Net income (loss)				48		47		46		45		45		44		43		93		87		141		132			177		133
Property and equipment, net				(2,790)		(2,745)		(2,754)		(2,732)		(2,749)		(2,715)		(2,700)		(2,745)		(2,715)		(2,790)		(2,749)			(2,732)
Assets				(2,790)		(2,745)		(2,754)		(2,732)		(2,749)		(2,715)		(2,700)		(2,745)		(2,715)		(2,790)		(2,749)			(2,732)
Deferred revenues				0	[3]	0	[3]	0	[3]	0	[2]	0	[3]	0	[3]	0	[3]	0	[3]	0	[3]	0	[3]	0	[3]		0	[2]
Liabilities, Current				0		0		0		0		0		0		0		0		0		0		0			0
Member's equity				(2,790)		(2,745)		(2,754)				(2,749)		(2,715)		(2,700)		(2,745)		(2,715)		(2,790)		(2,749)
Members' Equity				(2,790)		(2,745)		(2,754)		(2,732)		(2,749)		(2,715)		(2,700)		(2,745)		(2,715)		(2,790)		(2,749)			(2,732)		$ (2,688)	$ (1,582)
Other long-term liabilities(a)	[2]			0		0		0		0		0		0		0		0		0		0		0			0
Liabilities				0		0		0		$ 0		0		0		0		0		0		0		0			$ 0
Liabilities and Equity				$ (2,790)		$ (2,745)		$ (2,754)				$ (2,749)		$ (2,715)		$ (2,700)		$ (2,745)		$ (2,715)		$ (2,790)		$ (2,749)

[1] The sum of quarterly information may not agree to year-to-date information due to rounding. Resta

[2] (a) See "Recently Adopted Accounting Pronouncements" in note 3 to the consolidated financial statements for a discussion of the recently adopted lease standard.

[3] Reflects the recording of deferred revenues in connection with the CCIC transactions described in note 2 that result in permanent improvements to the Company's towers . The Company receives no cash from, and is not party to, such transactions.   September 30, 2018   June 30, 2018   March 31, 2018   (As Restated) ASSETS           Current assets:           Cash and cash equivalents $ 24,236
  $ 21,655
  $ 28,488
Receivables, net of allowance 2,740
  2,350
  2,744
Prepaid expenses^(a) 28,615
  27,444
  19,305
Deferred site rental receivables and other current assets 25,739
  39,928
  29,478
Total current assets 81,330
  91,377
  80,015
Deferred site rental receivables 341,633
  325,070
  331,907
Property and equipment, net 1,014,028
  1,017,638
  1,024,460
Goodwill 1,338,730
  1,338,730
  1,338,730
Other intangible assets, net^(a) 836,156
  864,946
  893,735
Long-term prepaid rent and other assets, net^(a) 39,252
  38,999
  38,789
Total assets $ 3,651,129
  $ 3,676,760
  $ 3,707,636
LIABILITIES AND EQUITY           Current liabilities:           Accounts payable $ 2,325
  $ 2,443
  $ 1,738
Accrued interest 17,748
  8,126
  17,748
Deferred revenues^(b) 57,765
  54,945
  52,855
Other accrued liabilities^(a) 8,835
  9,584
  12,589
Total current liabilities 86,673
  75,098
  84,930
Debt 993,701
  993,355
  993,009
Deferred ground lease payable^(a) 111,856
  110,349
  109,040
Other long-term liabilities^(a)(b) 207,270
  205,835
  206,141
Total liabilities 1,399,500
  1,384,637
  1,393,120
Commitments and contingencies (see note 10)           Member's equity:           Member's equity 2,251,629
  2,292,123
  2,314,516
Accumulated earnings (deficit) —
  —
  —
Total member's equity 2,251,629
  2,292,123
  2,314,516
Total liabilities and equity $ 3,651,129
  $ 3,676,760
  $ 3,707,636
     (a)