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Investments (Alternative Investment Portfolio by Strategy and the Remaining Commitment Amount and Maximum Exposure to Loss Associated With Each Strategy) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Carrying Amount	$ 446,805	$ 371,316
Private Equity Funds [Member]
Carrying Amount	306,357	280,980
Remaining Commitment	138,325	134,676
Maximum Exposure to Loss	444,682	415,656
Private Credit Funds [Member]
Carrying Amount	102,373	54,866
Remaining Commitment	89,809	89,481
Maximum Exposure to Loss	192,182	144,347
Real Assets [Member]
Carrying Amount	38,075	35,470
Remaining Commitment	19,161	21,945
Maximum Exposure to Loss	57,236	57,415
Alternative Investments [Member]
Carrying Amount	446,805	371,316
Remaining Commitment	247,295	246,102
Maximum Exposure to Loss	$ 694,100	$ 617,418

X

- 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.

+ Details

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X

- Definition

Fair value of investment other than investment in equity security, investment in debt security and equity method investment. Includes, but is not limited to, investment in certain entities that calculate net asset value per share. Example includes, but is not limited to, investment in hedge fund, venture capital fund, private equity fund, and real estate partnership or fund.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 54B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482134/820-10-35-54B

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-6A

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X

- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph b
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481203/810-10-50-4

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481203/810-10-50-6

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- Details

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- Details

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