DEFERRED REVENUE (Reconciliation of Deferred Revenue Balances) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
DEFERRED REVENUE [Abstract]
Balance at beginning of period	$ 210,200	$ 217,429	$ 214,060	$ 219,968
Amortization of deferred revenue	(2,068)	(1,778)	(5,928)	(4,317)
Balance at end of period	$ 208,132	$ 215,651	$ 208,132	$ 215,651