SHAREHOLDERS' EQUITY (Reconciliation of Changes in Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Before Tax [Roll Forward]
Comprehensive (loss) income before income taxes	$ (11,273)	$ 664	$ 1,440	$ 20,475
Income Tax [Roll Forward]
Other comprehensive income after reclassifications	1,643	152	(322)	(3,197)
Net [Roll Forward]
Accumulated other comprehensive income, beginning of period			1,941
Accumulated other comprehensive income, end of period	2,713		2,713
Accumulated Other Comprehensive Income [Member]
Before Tax [Roll Forward]
Accumulated other comprehensive income, beginning of period	8,247	15,201	3,323	6,111
Other comprehensive income before reclassifications	2,013	690	9,480	11,296
Reclassification adjustment for realized (gains) losses included in net income	(6,101)	(1,464)	(8,644)	(2,980)
Comprehensive (loss) income before income taxes	(4,088)	(774)	836	8,316
Accumulated other comprehensive income, end of period	4,159	14,427	4,159	14,427
Income Tax [Roll Forward]
Accumulated other comprehensive income, beginning of period	(3,164)	(5,596)	(1,199)	(2,247)
Other comprehensive income before reclassifications	(710)	(186)	(3,656)	(4,117)
Reclassification adjustment for realized (gains) losses included in net income	2,353	338	3,334	920
Other comprehensive income after reclassifications	1,643	152	(322)	(3,197)
Accumulated other comprehensive income, end of period	(1,521)	(5,444)	(1,521)	(5,444)
Net [Roll Forward]
Accumulated other comprehensive income, beginning of period	5,083	9,605	2,124	3,864
Other comprehensive income before reclassifications	1,303	504	5,824	7,179
Reclassification adjustment for realized (gains) losses included in net income	(3,748)	(1,126)	(5,310)	(2,060)
Other comprehensive income after reclassifications	(2,445)	(622)	514	5,119
Accumulated other comprehensive income, end of period	$ 2,638	$ 8,983	$ 2,638	$ 8,983