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Fair Value Measurement (Investments in LLCs and Limited Partnerships) (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
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Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] |  |
Fair Value | $ 251,675 | $ 246,259
Equity investments |  |
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] |  |
Fair Value | 251,675 | 233,711
Mortgage fund | Equity securities |  |
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] |  |
Unfunded Commitments | 0 |
Fair Value | 0 | 12,548
Private debt funds | Equity investments |  |
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] |  |
Unfunded Commitments | 8,929 |
Fair Value | 18,523 | 16,387
Long/short equity funds | Equity investments |  |
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] |  |
Unfunded Commitments | 0 |
Fair Value | 533 | 596
Non-public equity funds | Equity investments |  |
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] |  |
Unfunded Commitments | 38,713 |
Fair Value | 144,539 | 138,357
Credit funds | Equity investments |  |
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] |  |
Unfunded Commitments | 41,123 |
Fair Value | 43,125 | 34,848
Strategy focused funds | Equity investments |  |
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] |  |
Unfunded Commitments | 34,988 |
Fair Value | $ 44,955 | $ 43,523

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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 -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 6A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123874694&loc=SL6742756-110258 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 35 -Paragraph 54B -URI http://asc.fasb.org/extlink&oid=122636397&loc=SL7495116-110257 + Details
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- Definition 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. + References No definition available. + Details
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- Definition The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 6A -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=123874694&loc=SL6742756-110258 + Details
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