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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
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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

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- 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 + Details
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