DEFERRED REVENUE AND COSTS (DEFERRED COSTS CLASSIFICATION TABLE) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
DEFERRED REVENUE AND COSTS [ABSTRACT]
Deferred Costs - Current	$ 26,092	$ 23,539
Deferred Costs - Long-term	25,436	34,042
Total Deferred Costs	$ 51,528	$ 57,581