INVESTMENTS (DETAILS 2) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule Of Available For Sale Securities [Line Items]
Due in one year or less (amortized cost)	$ 496,073	$ 710,079
Due after one year through five years (amortized cost)	5,399,655	5,030,728
Due after five years through ten years (amortized cost)	1,907,336	1,852,877
Due after ten years (amortized cost)	235,045	97,364
Total fixed maturities with a single maturity date (amortized cost)	8,038,109	7,691,048
Total (amortized cost)	12,428,133	11,987,146
Due in one year or less (fair value)	502,045	717,052
Due after one year through five years (fair value)	5,503,744	5,116,060
Due after five years through ten years (fair value)	1,913,017	1,791,835
Due after ten years (fair value)	242,947	94,121
Total fixed maturities with a single maturity date (fair value)	8,161,753	7,719,068
Fair Value (fixed maturities)	12,598,897	11,986,327
Due in one year or less (% of total fair value)	4.00%	5.90%
Due after one year through five years (% of total fair value)	43.70%	42.70%
Due after five years through ten years (% of total fair value)	15.20%	14.90%
Due after ten years (% of total fair value)	1.90%	0.80%
Fixed maturities with a single maturity date (% of total fair value)	64.80%	64.30%
Total	100.00%	100.00%
Agency RMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fixed maturities without a single maturity date (amortized cost)	2,076,932	2,485,139
Total (amortized cost)	2,076,932	2,485,139
Fixed maturities without a single maturity date (fair value)	2,105,579	2,448,827
Fair Value (fixed maturities)	2,105,579	2,448,827
Fixed maturities without a single maturity date (% of total fair value)	16.70%	20.40%
CMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fixed maturities without a single maturity date (amortized cost)	923,294	790,095
Total (amortized cost)	923,294	790,095
Fixed maturities without a single maturity date (fair value)	939,694	797,414
Fair Value (fixed maturities)	939,694	797,414
Fixed maturities without a single maturity date (% of total fair value)	7.50%	6.70%
Non-Agency RMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fixed maturities without a single maturity date (amortized cost)	80,243	65,590
Total (amortized cost)	80,243	65,590
Fixed maturities without a single maturity date (fair value)	84,946	67,567
Fair Value (fixed maturities)	84,946	67,567
Fixed maturities without a single maturity date (% of total fair value)	0.70%	0.60%
ABS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fixed maturities without a single maturity date (amortized cost)	1,309,555	955,274
Total (amortized cost)	1,309,555	955,274
Fixed maturities without a single maturity date (fair value)	1,306,925	953,451
Fair Value (fixed maturities)	$ 1,306,925	$ 953,451
Fixed maturities without a single maturity date (% of total fair value)	10.30%	8.00%