Investments and Fair Value Measurements - Additional Information (Detail) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments	$ 16,000	$ 1,781,000
Fair Value, Measurements, Recurring
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Financial assets	0	0
Financial liabilities	$ 0	$ 0
Maximum
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Maximum financial interest in affiliated investment funds	2.00%

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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-Topic 820
-SubTopic 10
-Section 50
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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 25
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-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8813-108599

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 210
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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.

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Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

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