ACCOUNTS RECEIVABLE (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
ACCOUNTS RECEIVABLE
Accounts receivable	$ 58,568	$ 48,314
Less: allowance for doubtful accounts	(13,149)	(9,294)
Total accounts receivable, net	45,419	39,020
U.S. wireless, Retail
ACCOUNTS RECEIVABLE
Accounts receivable	36,026	23,805
U.S. wireless, Wholesale
ACCOUNTS RECEIVABLE
Accounts receivable	22,502	24,341
Other
ACCOUNTS RECEIVABLE
Accounts receivable	$ 40	$ 168