INVESTMENTS (Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Net Investment Income [Line Items]
Gross investment income	$ 100,429	$ 113,363
Investment expenses	(7,328)	(6,060)
Net investment income	93,101	107,303
Fixed maturities
Net Investment Income [Line Items]
Gross investment income	89,943	91,382
Other investments
Net Investment Income [Line Items]
Gross investment income	(2,120)	6,895
Equity securities
Net Investment Income [Line Items]
Gross investment income	2,125	2,328
Mortgage loans
Net Investment Income [Line Items]
Gross investment income	4,053	3,063
Cash and cash equivalents
Net Investment Income [Line Items]
Gross investment income	4,930	5,801
Short-term investments
Net Investment Income [Line Items]
Gross investment income	$ 1,498	$ 3,894

The net gain or loss (both realized and unrealized) related to investments in certain entities that calculate net asset value per share and the amount after accretion (amortization) of discount (premium), of interest income and dividend income on nonoperating securities.

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The net gain or loss (both realized and unrealized) related to investments in certain entities that calculate net asset value per share and the amount after accretion (amortization) of discount (premium) of interest income and dividend income on nonoperating securities, net of investment expense.

+ References

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Amount of expenses related to the generation of investment income.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.9)
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.2)
-URI http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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