Acquisitions (Schedule of Acquisition Capital Expenditures) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Acquisitions of towers and related intangible assets	$ 99,173	$ 110,464	$ 224,585	$ 372,054
Land buyouts and other assets	33,346	8,008	59,116	31,781
Total cash acquisition capital expenditures	132,519	118,472	283,701	403,835
Acquisition costs paid through the issuance of common stock			$ 1,700
Common stock issued for acquisition costs			10,000
Ground lease extensions	7,000	$ 6,700	$ 13,100	$ 16,400
Additional Interest in Unconsolidated Joint Venture [Member]
Business Acquisition [Line Items]
Consideration transferred	$ 72,000		$ 72,000