ACCUMULATED OTHER COMPREHENSIVE LOSS (Reclassified Out of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Unrealized holding gains on available-for-sale investments	$ (432)	$ (198)	$ (2,814)	$ (737)
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Unrealized holding gains on available-for-sale investments	$ 0	$ 0	$ 222	$ 0