OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Before Tax Amount
Other Comprehensive Income (Loss), before Tax	$ 87,860	$ 51,450	$ 213,859	$ 272,469
Tax (Expense) Benefit
Other Comprehensive Income (Loss), Tax	(4,253)	(6,008)	(7,712)	(20,915)
Net of Tax Amount
Adjustment for reclassification of net realized investment losses and OTTI losses recognized in net income	(1,503)	(14,019)	23,458	45,263
Other Comprehensive Income (Loss), Net of Tax	83,607	45,442	206,147	251,554
Unrealized gains (losses) on available for sale investments, net of tax [Member]
Before Tax Amount
Unrealized investment gains arising during the period	80,557	74,278	150,929	223,109
Adjustment for reclassification of net realized investment gains and OTTI losses recognized in net income	(1,564)	(18,604)	24,194	45,388
Other Comprehensive Income (Loss), before Tax	78,993	55,674	175,123	268,497
Tax (Expense) Benefit
Unrealized investment gains arising during the period	(4,314)	(10,593)	(6,976)	(20,790)
Adjustment for reclassification of net realized investment gains and OTTI losses recognized in net income	61	4,585	(736)	(125)
Other Comprehensive Income (Loss), Tax	(4,253)	(6,008)	(7,712)	(20,915)
Net of Tax Amount
Unrealized investment gains arising during the period	76,243	63,685	143,953	202,319
Adjustment for reclassification of net realized investment losses and OTTI losses recognized in net income	(1,503)	(14,019)	23,458	45,263
Other Comprehensive Income (Loss), Net of Tax	74,740	49,666	167,411	247,582
Accumulated Other-than-Temporary Impairment, net of tax [Member]
Before Tax Amount
Other Comprehensive Income (Loss), before Tax	0	0	0	0
Tax (Expense) Benefit
Other Comprehensive Income (Loss), Tax	0	0	0	0
Net of Tax Amount
Other Comprehensive Income (Loss), Net of Tax	0	0	0	0
Cumulative foreign currency translation adjustments, net of tax [Member]
Before Tax Amount
Other Comprehensive Income (Loss), before Tax	8,867	(4,224)	38,736	3,972
Tax (Expense) Benefit
Other Comprehensive Income (Loss), Tax	0	0	0	0
Net of Tax Amount
Other Comprehensive Income (Loss), Net of Tax	$ 8,867	$ (4,224)	$ 38,736	$ 3,972