SUMMARY OF INVESTMENTS (Maturities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Held-To-Maturity, Amortized Cost
Held-to-maturity securities, amortized cost	$ 672	$ 397
Held-To-Maturity, Fair Value
Held-to-maturity securities	675	404
Available-For-Sale, Amortized Cost
Available-for-sale securities, amortized cost	2,861,583	2,845,217
Available-For-Sale, Fair Value
Available-for-sale securities	3,061,208	3,088,922
Trading, Fair Value
Trading securities, fair value	12,622	16,862
Asset-backed Securities [Member]
Available-For-Sale, Amortized Cost
Available-for-sale securities, amortized cost	5,461	2,741
Available-For-Sale, Fair Value
Available-for-sale securities	5,666	3,018
Mortgage-Backed Securities [Member]
Held-To-Maturity, Amortized Cost
Held-to-maturity securities, amortized cost	72	142
Held-To-Maturity, Fair Value
Held-to-maturity securities	74	149
Available-For-Sale, Amortized Cost
Available-for-sale securities, amortized cost	16,413	17,121
Available-For-Sale, Fair Value
Available-for-sale securities	16,738	17,558
Collateralized Mortgage Obligations [Member]
Available-For-Sale, Amortized Cost
Available-for-sale securities, amortized cost	364,115	335,092
Available-For-Sale, Fair Value
Available-for-sale securities	366,015	$ 337,289
Fixed Maturities [Member]
Held-To-Maturity, Amortized Cost
Due in one year or less	0
Due after one year through five years	600
Due after five years through 10 years	0
Due after 10 years	0
Held-to-maturity securities, amortized cost	672
Held-To-Maturity, Fair Value
Due in one year or less	0
Due after one year through five years	601
Due after five years through 10 years	0
Due after 10 years	0
Held-to-maturity securities	675
Available-For-Sale, Amortized Cost
Due in one year or less	105,186
Due after one year through five years	819,617
Due after five years through 10 years	989,897
Due after 10 years	492,380
Available-for-sale securities, amortized cost	2,793,069
Available-For-Sale, Fair Value
Due in one year or less	105,910
Due after one year through five years	840,292
Due after five years through 10 years	989,295
Due after 10 years	501,045
Available-for-sale securities	2,824,961
Trading, Amortized Cost
Due in one year or less	1,526
Due after one year through five years	7,596
Due after five years through 10 years	130
Due after 10 years	2,223
Trading securities, amortized cost	11,475
Trading, Fair Value
Due in one year or less	2,001
Due after one year through five years	7,676
Due after five years through 10 years	404
Due after 10 years	2,541
Trading securities, fair value	12,622
Fixed Maturities [Member] | Asset-backed Securities [Member]
Held-To-Maturity, Amortized Cost
Not categorized by contractual maturity	0
Held-To-Maturity, Fair Value
Not categorized by contractual maturity	0
Available-For-Sale, Amortized Cost
Not categorized by contractual maturity	5,461
Available-For-Sale, Fair Value
Not categorized by contractual maturity	5,666
Fixed Maturities [Member] | Mortgage-Backed Securities [Member]
Held-To-Maturity, Amortized Cost
Not categorized by contractual maturity	72
Held-To-Maturity, Fair Value
Not categorized by contractual maturity	74
Available-For-Sale, Amortized Cost
Not categorized by contractual maturity	16,413
Available-For-Sale, Fair Value
Not categorized by contractual maturity	16,738
Fixed Maturities [Member] | Collateralized Mortgage Obligations [Member]
Held-To-Maturity, Amortized Cost
Not categorized by contractual maturity	0
Held-To-Maturity, Fair Value
Not categorized by contractual maturity	0
Available-For-Sale, Amortized Cost
Not categorized by contractual maturity	364,115
Available-For-Sale, Fair Value
Not categorized by contractual maturity	$ 366,015