FAIR VALUE (Financial Instruments Measured at Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Debt securities	$ 374,756	$ 339,178
Equity securities	29,375	38,534
Total investments	404,131	377,712
United States Government Obligations and Authorities [Member]
Investments, Debt and Equity Securities [Abstract]
Debt securities	62,205	61,553
Total investments	62,205	61,553
Obligations of States and Political Subdivisions [Member]
Investments, Debt and Equity Securities [Abstract]
Debt securities	151,183	110,702
Total investments	151,183	110,702
Corporate [Member]
Investments, Debt and Equity Securities [Abstract]
Debt securities	149,505	154,620
Total investments	149,505	154,620
International [Member]
Investments, Debt and Equity Securities [Abstract]
Debt securities	11,863	12,303
Total investments	11,863	12,303
Level 1 [Member]
Investments, Debt and Equity Securities [Abstract]
Debt securities	36,560	34,733
Equity securities	28,960	38,012
Total investments	65,520	72,745
Level 1 [Member] | United States Government Obligations and Authorities [Member]
Investments, Debt and Equity Securities [Abstract]
Debt securities	36,560	34,733
Level 2 [Member]
Investments, Debt and Equity Securities [Abstract]
Debt securities	338,196	304,445
Equity securities	415	522
Total investments	338,611	304,967
Level 2 [Member] | United States Government Obligations and Authorities [Member]
Investments, Debt and Equity Securities [Abstract]
Debt securities	25,645	26,820
Level 2 [Member] | Obligations of States and Political Subdivisions [Member]
Investments, Debt and Equity Securities [Abstract]
Debt securities	151,183	110,702
Level 2 [Member] | Corporate [Member]
Investments, Debt and Equity Securities [Abstract]
Debt securities	149,505	154,620
Level 2 [Member] | International [Member]
Investments, Debt and Equity Securities [Abstract]
Debt securities	$ 11,863	$ 12,303