Fair Value Measurements - Investments in Company-Sponsored Funds (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2020	Dec. 31, 2019
Investment Holdings [Line Items]
Fair Value	$ 5,489	$ 5,816
Unfunded Commitments	$ 1,238	1,339
Hedge Funds [Member]
Investment Holdings [Line Items]
Investment Redemption Notice Period Minimum	30 days
Investment Redemption Notice Period Maximum	120 days
Fair Value	$ 1,138	1,589
Unfunded Commitments	$ 0	$ 0
Redemption Frequency	Quarterly - Annually	Quarterly - Annually
Private Equity Funds
Investment Holdings [Line Items]
Fair Value	$ 4,351	$ 4,227
Unfunded Commitments	$ 1,238	$ 1,339

Investment redemption frequency.

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Investment redemption notice period maximum.

+ References

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Investment redemption notice period minimum.

+ References

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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=117815213&loc=SL6742756-110258

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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.

+ References

No definition available.

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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