SUMMARY OF INVESTMENTS (Net Investment Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Other	$ 1,452	$ 1,998	$ 1,632
Total investment income	107,818	110,925	118,123
Less investment expenses	7,037	6,316	5,324
Net investment income	100,781	104,609	112,799
Fixed Maturities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Interest income	92,777	97,969	101,950
Equity Securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Dividends on equity securities	7,208	6,602	5,806
Other Long-term Investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Interest income	2,567	1,927	1,194
Other Long-term Investments [Member] | Change in Value [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Other	3,266	1,917	7,030
Mortgage Loans [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Interest income	237	252	266
Short-term Investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Interest income	6	5	6
Cash and Cash Equivalents [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Interest income	$ 305	$ 255	$ 239