INVESTMENTS (Summary of Amortized Cost and Fair Value of Debt and Equity Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Investments [Line Items]
Debt securities, available-for-sale, at amortized cost	$ 439,254	$ 433,664
Debt securities - available-for-sale, at fair value:	443,458	428,641
Held-to-maturity securities, Amortized Cost or Cost	4,552	5,126
Total investments, Amortized Cost or Cost	443,806	438,790
Total investments, Gross Unrealized Gain	6,041	1,643
Total investments, Gross Unrealized Loss	1,920	6,828
Total investments, Fair Value	447,927	433,605
Debt Securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, at amortized cost	439,254	433,664
Debt securities, available-for-sale securities, Gross Unrealized Gain	6,031	1,640
Debt securities, available-for-sale securities, Gross Unrealized Losses	1,827	6,663
Debt securities - available-for-sale, at fair value:	443,458	428,641
Held-to-maturity securities, Amortized Cost or Cost	4,552	5,126
Held-to-maturity securities, Gross Unrealized Gains	10	3
Held-to-maturity securities, Gross Unrealized Losses	93	165
Held-to-maturity securities, fair value	4,469	4,964
United States Government Obligations and Authorities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, at amortized cost	144,450	127,928
Debt securities, available-for-sale securities, Gross Unrealized Gain	2,037	1,091
Debt securities, available-for-sale securities, Gross Unrealized Losses	525	1,151
Debt securities - available-for-sale, at fair value:	145,962	127,868
Held-to-maturity securities, Amortized Cost or Cost	3,567	4,085
Held-to-maturity securities, Gross Unrealized Gains	2	1
Held-to-maturity securities, Gross Unrealized Losses	91	158
Held-to-maturity securities, fair value	3,478	3,928
Obligations of States and Political Subdivisions
Schedule of Investments [Line Items]
Debt securities, available-for-sale, at amortized cost	11,502	9,870
Debt securities, available-for-sale securities, Gross Unrealized Gain	88	27
Debt securities, available-for-sale securities, Gross Unrealized Losses	71	130
Debt securities - available-for-sale, at fair value:	11,519	9,767
Corporate
Schedule of Investments [Line Items]
Debt securities, available-for-sale, at amortized cost	260,844	273,192
Debt securities, available-for-sale securities, Gross Unrealized Gain	3,693	510
Debt securities, available-for-sale securities, Gross Unrealized Losses	1,152	4,971
Debt securities - available-for-sale, at fair value:	263,385	268,731
Held-to-maturity securities, Amortized Cost or Cost	930	986
Held-to-maturity securities, Gross Unrealized Gains	8	2
Held-to-maturity securities, Gross Unrealized Losses	2	6
Held-to-maturity securities, fair value	936	982
International
Schedule of Investments [Line Items]
Debt securities, available-for-sale, at amortized cost	22,458	22,674
Debt securities, available-for-sale securities, Gross Unrealized Gain	213	12
Debt securities, available-for-sale securities, Gross Unrealized Losses	79	411
Debt securities - available-for-sale, at fair value:	22,592	22,275
Held-to-maturity securities, Amortized Cost or Cost	55	55
Held-to-maturity securities, Gross Unrealized Gains	0	0
Held-to-maturity securities, Gross Unrealized Losses	0	1
Held-to-maturity securities, fair value	$ 55	$ 54