REVENUE AND RECEIVABLES - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Contract Assets and Liabilities
Contract Asset - current	$ 2,478
Change in contract asset - current	2,327
Contract Asset - current	$ 4,805	$ 2,478
% of change in contract asset - current	94.00%
Contract asset, noncurrent	$ 910
Change in contract asset - noncurrent	(10)
Contract asset, noncurrent	$ 900	910
% of change in contract asset - noncurrent	(1.00%)
Contract liability- current	$ (18,544)
Change in contract liabilities - current	(6,788)
Contract liability- current	$ (25,332)	(18,544)
% of change in contract liabilities - current	(37.00%)
Contract liability- noncurrent	$ (2,193)
Change in contract liabilities - noncurrent	(79,198)
Contract liability- noncurrent	$ (81,391)	(2,193)
% of change in contract liabilities - Noncurrent	(3611.00%)
Net contract liability	$ (17,349)
Change in net contract liability	(83,669)
Net contract liability	$ (101,018)	(17,349)
% of change in net contract liability	(482.00%)
Revenue recognized related to contract liability	$ 18,000	16,900
Amortization of contract assets	2,400	2,300
Revenue recognized in the period related to performance obligations that were satisfied or partially satisfied in previous periods	$ 0	$ 0
Retail revenue period for billing postpaid customers in advance	1 month