SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 6) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Proceeds collected through a surcharge on certain customers' bills	$ 600	$ 500
Cash and cash equivalents	42,653	47,176
Restricted cash (included in taxes, prepaid expenses, and other assets)	645	539
Total cash, cash equivalents, and restricted cash shown in the statements of cash flows	$ 43,298	$ 47,715	$ 95,300	$ 25,935