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Investments (Other Investment Portfolio by Strategy and the Remaining Commitment Amount Associated With Each Strategy) (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Carrying Value		$ 216,807	$ 178,938
Other Securities [Member]
Carrying Value	[1]	32,667	25,042
Remaining Commitment	[1]	0	0
Maximum Exposure to Loss	[1]	32,667	25,042
Real Assets [Member]
Carrying Value		23,256	27,862
Remaining Commitment		20,741	27,129
Maximum Exposure to Loss		43,997	54,991
Private Credit Funds [Member]
Carrying Value		42,532	41,682
Remaining Commitment		105,340	81,453
Maximum Exposure to Loss		147,872	123,135
Private Equity [Member]
Carrying Value		118,352	84,352
Remaining Commitment		93,138	93,688
Maximum Exposure to Loss		211,490	178,040
Other Investment Portfolio [Member]
Carrying Value		216,807	178,938
Remaining Commitment		219,219	202,270
Maximum Exposure to Loss		436,026	381,208
Alternative Investments [Member]
Carrying Value		184,140	153,896
Remaining Commitment		219,219	202,270
Maximum Exposure to Loss		$ 403,359	$ 356,166
[1] Other securities primarily consists of tax credit investments.

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- Definition

This item represents contractual obligations to invest additional amounts on our other investment portfolio. These additional investments may or may not be required.

+ References

No definition available.

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- Definition

Amount of investments classified as other.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(f,g))
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The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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