INVESTMENTS (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Amortized Cost
Due in one year or less	$ 22,792
Due after one year through five years	304,023
Due after five years through 10 years	567,054
Due after 10 years	287,038
Total amoritzed cost	1,512,806	$ 1,518,156
Fair Value
Due in one year or less	22,975
Due after one year through five years	307,732
Due after five years through 10 years	585,434
Due after 10 years	298,714
Total fair value	1,556,968	1,538,110
Fair value measured on recurring basis
Available-for-sale
Fair Value	1,946,519	1,913,534
Fair value measured on recurring basis \| Significant Unobservable Inputs (Level 3)
INVESTMENTS
Total assets at fair value	0
Debt securities
Available-for-sale
Available-for-sale Securities, Amortized Cost Basis, Total	1,512,806	1,518,156
Gross Unrealized Gains	55,434	37,750
Gross Unrealized Losses	(11,272)	(17,796)
Fair Value	1,556,968	1,538,110
U.S. government
Available-for-sale
Available-for-sale Securities, Amortized Cost Basis, Total	86,872	43,597
Gross Unrealized Gains	1,333	58
Gross Unrealized Losses		(112)
Fair Value	88,205	43,543
U.S. Agency
Available-for-sale
Available-for-sale Securities, Amortized Cost Basis, Total	15,482	15,481
Gross Unrealized Gains	761	306
Gross Unrealized Losses	(1)	(47)
Fair Value	16,242	15,740
Non-U.S. govt. & agency
Available-for-sale
Available-for-sale Securities, Amortized Cost Basis, Total	7,009	5,035
Gross Unrealized Gains	87
Gross Unrealized Losses	(317)	(557)
Fair Value	6,779	4,478
Agency MBS
Available-for-sale
Available-for-sale Securities, Amortized Cost Basis, Total	242,377	250,060
Gross Unrealized Gains	8,736	6,451
Gross Unrealized Losses	(298)	(1,619)
Fair Value	250,815	254,892
ABS/CMBS
Available-for-sale
Available-for-sale Securities, Amortized Cost Basis, Total	89,522	91,559
Gross Unrealized Gains	1,899	995
Gross Unrealized Losses	(123)	(606)
Fair Value	91,298	91,948
Corporate
Available-for-sale
Available-for-sale Securities, Amortized Cost Basis, Total	554,865	523,351
Gross Unrealized Gains	15,656	8,565
Gross Unrealized Losses	(10,532)	(14,807)
Fair Value	559,989	517,109
Municipal
Available-for-sale
Available-for-sale Securities, Amortized Cost Basis, Total	516,679	589,073
Gross Unrealized Gains	26,962	21,375
Gross Unrealized Losses	(1)	(48)
Fair Value	543,640	610,400
Mtge/ABS/CMBS
Available-for-sale
Available-for-sale Securities, Amortized Cost Basis, Total	331,899
Fair Value	342,113
Equity securities
Available-for-sale
Available-for-sale Securities, Amortized Cost Basis, Total	207,302	202,437
Gross Unrealized Gains	183,020	174,443
Gross Unrealized Losses	(771)	(1,456)
Fair Value	$ 389,551	$ 375,424

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 820
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