REVENUE RECOGNITION, Contract Assets and Contract Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Contract with Customer, Asset and Liability [Abstract]
Total Deferred Revenue	$ 1,450	$ 1,301
Tariff Revenue [Member]
Contract with Customer, Asset and Liability [Abstract]
Contract Assets	2,175	2,146
Total Deferred Revenue	1,150	1,050
Tariff Deferred Revenue	1,100
Non-Tariff Revenue [Member]
Contract with Customer, Asset and Liability [Abstract]
Total Deferred Revenue	300	$ 251
Tariff Deferred Revenue	$ 200