Schedule III - Schedule of Real Estate and Accumulated Depreciation (Reconciliation of Carrying Amount of Real Estate Investments) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) item	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Gross amount at beginning	$ 5,963,048	$ 5,833,338	$ 5,561,005
Acquisitions	995,063	80,582	111,734
Construction and related costs on new builds	45,802	40,493	48,975
Augmentation and tower upgrades	32,953	36,211	63,998
Land buyouts and other assets	24,944	28,918	39,298
Tower maintenance	34,611	28,426	28,960
Other	20,052	19,142
Total additions	1,153,425	233,772	292,965
Cost of real estate sold or disposed	(192)		(856)
Impairment	(15,552)	(17,064)	(9,587)
Other	(32,521)	(86,998)	(10,189)
Total deductions	(48,265)	(104,062)	(20,632)
Balance at end	$ 7,068,208	$ 5,963,048	$ 5,833,338
Exclusive Right to Lease and Operate Utility Transmission Structures [Member]
Number of utility transmission structures acquired | item	713