Concentration of Credit Risk

12 Months Ended

Dec. 31, 2019

Concentration of Credit Risk [Abstract]

Concentration of Credit Risk

18.CONCENTRATION OF CREDIT RISK

The Company’s credit risks consist primarily of accounts receivable with national, regional, and local wireless service providers and federal and state government agencies. The Company performs periodic credit evaluations of its customers’ financial condition and provides allowances for doubtful accounts, as required, based upon factors surrounding the credit risk of specific customers, historical trends, and other information. The Company generally does not require collateral.

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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	2019	2018	2017
AT&T Wireless	23.8%	24.0%	25.0%
T-Mobile	18.2%	16.4%	16.5%
Sprint	16.9%	17.9%	15.1%
Verizon Wireless	14.0%	14.7%	15.2%

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	2019	2018	2017
AT&T Wireless	32.1%	31.9%	32.7%
T-Mobile	21.6%	20.3%	19.7%
Sprint	19.0%	19.6%	18.9%
Verizon Wireless	18.6%	19.0%	19.0%
	For the year ended December 31,
Percentage of International Site Leasing Revenue	2019	2018	2017
Oi S.A.	31.3%	35.5%	42.2%
Telefonica	26.9%	26.7%	25.7%
Claro	11.6%	11.4%	10.0%

	For the year ended December 31,
Percentage of Site Development Revenue	2019	2018	2017
Sprint	37.3%	47.1%	12.9%
T-Mobile	30.2%	16.4%	26.9%
Verizon Wireless	2.9%	6.4%	12.8%
Nokia, Inc.	4.3%	3.2%	10.1%

Five customers comprised 66.6% of total gross accounts receivable at December 31, 2019 compared to five customers which comprised 67.5% of total gross accounts receivable at December 31, 2018.