Summary of Financial Instruments for Which Fair Value Option Has Been Elected (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans and Receivables	$ 307,288	$ 315,039
Assets	2,711,651	2,208,015
Liabilities	298,292	8,144
Debt Securities
Fair Value, Option, Quantitative Disclosures [Line Items]
Investments	65,077	24,784
Equity and Preferred Securities
Fair Value, Option, Quantitative Disclosures [Line Items]
Investments	2,082,976	1,868,192
Corporate Loans
Fair Value, Option, Quantitative Disclosures [Line Items]
Assets	256,310	0
CLO Notes Payable
Fair Value, Option, Quantitative Disclosures [Line Items]
Liabilities	292,374	0
Corporate Treasury Commitments
Fair Value, Option, Quantitative Disclosures [Line Items]
Liabilities	$ 5,918	$ 8,144

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

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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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- Definition

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.

+ References

No definition available.

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- Definition

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 https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI https://asc.fasb.org/subtopic&trid=2196772

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