DEFERRED REVENUE (Reconciliation of Deferred Revenue Balances) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
DEFERRED REVENUE [Abstract]
Balance at beginning of period	$ 212,292	$ 218,987	$ 214,060	$ 219,968
Amortization of deferred revenue	(2,092)	(1,558)	(3,860)	(2,539)
Balance at end of period	$ 210,200	$ 217,429	$ 210,200	$ 217,429