Concentrations of Credit Risk (Tables)

3 Months Ended

Mar. 31, 2014

Concentrations of Credit Risk [Abstract]

Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]

Major Customers

The following table summarizes the percentage of the consolidated revenues for those customers accounting for more than 10% of the consolidated revenues (all of such customer revenues relate to our CCUSA segment). The following table is after giving effect to AT&T's acquisition of Leap Wireless (completed in March 2014).

	Three Months Ended March 31,
	2014		2013
AT&T	27	%	21	%
Sprint	26	%	28	%
T-Mobile	21	%	23	%
Verizon Wireless	15	%	15	%
Total	89	%	87	%