Concentration Of Credit Risk (Tables)

12 Months Ended

Dec. 31, 2016

Concentration Of Credit Risk [Abstract]

Summary Of Significant Customers And Percentage Of Total Revenue For Specified Time Periods Derived From Such Customers

The following is a list of significant customers (representing at least 10% of revenue for any period reported) and the percentage of total revenue for the specified time periods derived from such customers:

	For the year ended December 31,
Percentage of Total Revenues	2016	2015	2014
AT&T Wireless (1)	25.7%	24.2%	23.0%
T-Mobile	17.0%	16.0%	15.5%
Sprint	16.1%	19.6%	23.4%
Verizon Wireless	15.2%	13.8%	12.0%

The Company’s site leasing and site development segments derive revenue from these customers. Client percentages of total revenue in each of the segments are as follows:

	For the year ended December 31,
Percentage of Domestic Site Leasing Revenue	2016	2015	2014
AT&T Wireless (1)	32.7%	31.9%	30.1%
Sprint	19.8%	22.3%	25.6%
T-Mobile	19.6%	19.0%	19.2%
Verizon Wireless	18.2%	16.3%	14.4%
	For the year ended December 31,
Percentage of International Site Leasing Revenue	2016	2015	2014
Oi S.A.	43.9%	48.8%	44.3%
Telefonica	26.4%	24.7%	28.8%

	For the year ended December 31,
Percentage of Site Development Revenue	2016	2015	2014
T-Mobile	28.4%	17.6%	8.5%
Verizon Wireless	16.5%	14.8%	10.1%
Sprint	11.7%	28.5%	36.7%
Ericsson, Inc.	5.0%	15.3%	16.8%

(1)Prior year amounts have been adjusted to reflect the merger of AT&T Wireless and Leap Wireless (Cricket Wireless).