INVESTMENTS (DETAILS 3) $ in Thousands	Dec. 31, 2016 USD ($) security	Dec. 31, 2015 USD ($) security
Schedule Of Available For Sale Securities [Line Items]
Total Unrealized Losses	$ (197,000)	$ (230,000)
Fixed Maturities [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	971,489	1,317,794
Unrealized Losses - 12 months or greater	(77,645)	(106,770)
Fair Value - Less than 12 months	5,833,715	7,145,067
Unrealized Losses - Less than 12 months	(119,550)	(123,638)
Total Fair Value of Securities in Unrealized Loss Position	6,805,204	8,462,861
Total Unrealized Losses	$ (197,195)	$ (230,408)
Number of available for sale securities in unrealized loss positions | security	1,881	2,314
Number of available for sale securities in unrealized loss positions for 12 months or greater | security	330	383
Fixed Maturities [Member] | Below Investment Grade or Not Rated [Member]
Schedule Of Available For Sale Securities [Line Items]
Total Unrealized Losses	$ (15,000)	$ (39,000)
US Government and Agency [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	54,051	84,179
Unrealized Losses - 12 months or greater	(2,729)	(7,622)
Fair Value - Less than 12 months	1,340,719	1,474,202
Unrealized Losses - Less than 12 months	(24,275)	(15,591)
Total Fair Value of Securities in Unrealized Loss Position	1,394,770	1,558,381
Total Unrealized Losses	(27,004)	(23,213)
Non-US Government [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	149,360	170,269
Unrealized Losses - 12 months or greater	(38,683)	(50,841)
Fair Value - Less than 12 months	283,796	317,693
Unrealized Losses - Less than 12 months	(10,971)	(21,491)
Total Fair Value of Securities in Unrealized Loss Position	433,156	487,962
Total Unrealized Losses	(49,654)	(72,332)
Corporate Debt [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	230,218	340,831
Unrealized Losses - 12 months or greater	(30,652)	(33,441)
Fair Value - Less than 12 months	1,948,976	2,845,375
Unrealized Losses - Less than 12 months	(44,488)	(62,845)
Total Fair Value of Securities in Unrealized Loss Position	2,179,194	3,186,206
Total Unrealized Losses	(75,140)	(96,286)
Agency RMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	76,694	64,792
Unrealized Losses - 12 months or greater	(1,101)	(1,609)
Fair Value - Less than 12 months	1,724,170	1,073,566
Unrealized Losses - Less than 12 months	(34,876)	(8,066)
Total Fair Value of Securities in Unrealized Loss Position	1,800,864	1,138,358
Total Unrealized Losses	(35,977)	(9,675)
CMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	84,640	75,627
Unrealized Losses - 12 months or greater	(749)	(1,579)
Fair Value - Less than 12 months	193,499	659,480
Unrealized Losses - Less than 12 months	(2,815)	(7,603)
Total Fair Value of Securities in Unrealized Loss Position	278,139	735,107
Total Unrealized Losses	(3,564)	(9,182)
Non-Agency RMBS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	13,642	5,283
Unrealized Losses - 12 months or greater	(1,752)	(210)
Fair Value - Less than 12 months	7,194	43,199
Unrealized Losses - Less than 12 months	(271)	(763)
Total Fair Value of Securities in Unrealized Loss Position	20,836	48,482
Total Unrealized Losses	(2,023)	(973)
ABS [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	362,110	562,599
Unrealized Losses - 12 months or greater	(1,950)	(11,158)
Fair Value - Less than 12 months	266,763	667,448
Unrealized Losses - Less than 12 months	(893)	(6,443)
Total Fair Value of Securities in Unrealized Loss Position	628,873	1,230,047
Total Unrealized Losses	(2,843)	(17,601)
Municipals [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	774	14,214
Unrealized Losses - 12 months or greater	(29)	(310)
Fair Value - Less than 12 months	68,598	64,104
Unrealized Losses - Less than 12 months	(961)	(836)
Total Fair Value of Securities in Unrealized Loss Position	69,372	78,318
Total Unrealized Losses	(990)	(1,146)
Equity Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	4,959	2,331
Unrealized Losses - 12 months or greater	(461)	(313)
Fair Value - Less than 12 months	211,751	234,997
Unrealized Losses - Less than 12 months	(11,607)	(8,676)
Total Fair Value of Securities in Unrealized Loss Position	216,710	237,328
Total Unrealized Losses	$ (12,068)	$ (8,989)
Number of available for sale securities in unrealized loss positions | security	23	35
Number of available for sale securities in unrealized loss positions for 12 months or greater | security	3	1
Common Stock [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	$ 0	$ 0
Unrealized Losses - 12 months or greater	0	0
Fair Value - Less than 12 months	37	0
Unrealized Losses - Less than 12 months	(342)	0
Total Fair Value of Securities in Unrealized Loss Position	37	0
Total Unrealized Losses	(342)	0
Exchange-Traded Funds [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	4,959	2,331
Unrealized Losses - 12 months or greater	(461)	(313)
Fair Value - Less than 12 months	87,760	110,972
Unrealized Losses - Less than 12 months	(2,173)	(4,449)
Total Fair Value of Securities in Unrealized Loss Position	92,719	113,303
Total Unrealized Losses	(2,634)	(4,762)
Bond Mutual Funds [Member]
Schedule Of Available For Sale Securities [Line Items]
Fair Value - 12 months or greater	0	0
Unrealized Losses - 12 months or greater	0	0
Fair Value - Less than 12 months	123,954	124,025
Unrealized Losses - Less than 12 months	(9,092)	(4,227)
Total Fair Value of Securities in Unrealized Loss Position	123,954	124,025
Total Unrealized Losses	$ (9,092)	$ (4,227)