Segment Data (Narrative) (Details) $ in Thousands	12 Months Ended			36 Months Ended
	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of business segments | segment	2
Number of reportable segments | segment	2
Site leasing	$ 1,954,472	$ 1,860,858	$ 1,740,434
Total assets	9,158,018	9,759,941		$ 9,158,018
Brazil [Member]
Segment Reporting Information [Line Items]
Site leasing	222,600	226,700	$ 221,500
Total assets	$ 1,000	$ 1,400		$ 1,000
Revenue [Member] | Foreign Countries, Other than Brazil [Member] | Maximum [Member]
Segment Reporting Information [Line Items]
Concentration risk percentage of revenue				4.00%