Fair Value Measurements (Summary of Asset Impairment and Decommission Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair Value Measurements [Abstract]
Asset impairment	$ 24,813	$ 31,552	$ 18,794
Write-off of carrying value of decommissioned towers	6,349	7,456	11,155
Other (including third party decommission costs)	1,882	1,089	3,154
Total asset impairment and decommission costs	$ 33,044	$ 40,097	$ 33,103