INVESTMENTS (DETAILS 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Available For Sale Securities [Line Items]
Due in one year or less (amortized cost)	$ 710,079	$ 651,111
Due after one year through five years (amortized cost)	5,030,728	4,880,039
Due after five years through ten years (amortized cost)	1,852,877	1,847,295
Due after ten years (amortized cost)	97,364	85,956
Total fixed maturities with a single maturity date (amortized cost)	7,691,048	7,464,401
Total (amortized cost)	11,987,146	11,605,672
Due in one year or less (fair value)	717,052	657,045
Due after one year through five years (fair value)	5,116,060	4,989,151
Due after five years through ten years (fair value)	1,791,835	1,951,569
Due after ten years (fair value)	94,121	91,887
Total fixed maturities with a single maturity date (fair value)	7,719,068	7,689,652
Fair Value (fixed maturities)	11,986,327	11,928,049
Due in one year or less (% of total fair value)	5.90%	5.50%
Due after one year through five years (% of total fair value)	42.70%	41.80%
Due after five years through ten years (% of total fair value)	14.90%	16.40%
Due after ten years (% of total fair value)	0.80%	0.80%
Fixed maturities with single maturity date (% of total fair value)	64.30%	64.50%
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)	2,485,139	2,594,180
Total (amortized cost)	2,485,139	2,594,180
Fixed maturities without a single maturity date (fair value)	2,448,827	2,659,908
Fair Value (fixed maturities)	2,448,827	2,659,908
Fixed maturities without a single maturity date (% of total fair value)	20.40%	22.30%
CMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fixed maturities without a single maturity date (amortized cost)	790,095	814,211
Total (amortized cost)	790,095	814,211
Fixed maturities without a single maturity date (fair value)	797,414	840,084
Fair Value (fixed maturities)	797,414	840,084
Fixed maturities without a single maturity date (% of total fair value)	6.70%	7.00%
Non-Agency RMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fixed maturities without a single maturity date (amortized cost)	65,590	93,266
Total (amortized cost)	65,590	93,266
Fixed maturities without a single maturity date (fair value)	67,567	95,199
Fair Value (fixed maturities)	67,567	95,199
Fixed maturities without a single maturity date (% of total fair value)	0.60%	0.80%
ABS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fixed maturities without a single maturity date (amortized cost)	955,274	639,614
Total (amortized cost)	955,274	639,614
Fixed maturities without a single maturity date (fair value)	953,451	643,206
Fair Value (fixed maturities)	$ 953,451	$ 643,206
Fixed maturities without a single maturity date (% of total fair value)	8.00%	5.40%