INVESTMENTS (Net Realized Gains (Losses) by Major Investment Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Gross realized gains and losses [Abstract]
Total gross realized gains	$ 7,472	$ 6,231	$ 5,214
Total gross realized losses	(4,427)	(2,615)	(788)
Net realized gains on investments	3,045	3,616	4,426
Debt Securities [Member]
Gross realized gains and losses [Abstract]
Total gross realized gains	3,208	1,272	725
Total gross realized losses	(1,614)	(805)	(147)
Equity Securities [Member]
Gross realized gains and losses [Abstract]
Total gross realized gains	4,264	4,959	4,489
Total gross realized losses	$ (2,813)	$ (1,810)	$ (641)