Fair Value Measurements - Fair Value Reconciliation (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Loans
Fair value of loans held for sale	$ 407,773	$ 110,400
Balance at Fair Value
Loans
Fair value of loans held for investment	4,675,354	4,941,825
Other asset-backed securities related to Structured Program transactions
Loans
Interest income accretion and fair value adjustments recorded in earnings, and change in unrealized gain	42
Senior asset-backed securities related to Structured Program transactions
Loans
Beginning	0
Originations and purchases, and additions	1,225,796
Principal payments and cash received	(60,283)
Interest income accretion and fair value adjustments recorded in earnings, and change in unrealized gain	10,890
Ending	1,176,403	0
Other asset-backed securities related to Structured Program transactions
Loans
Beginning	12,469
Originations and purchases, and additions	73,516
Principal payments and cash received	(12,634)
Ending	73,393	12,469
Loans Held For Sale
Loans
Beginning	110,400	142,370
Originations and purchases, and additions	4,942,457	9,045,701
Sales	(4,634,155)	(9,039,892)
Principal payments and cash received	(70,350)	(31,253)
Transfers	195,106	(11,907)
Interest income accretion and fair value adjustments recorded in earnings, and change in unrealized gain	(135,685)	5,381
Ending	407,773	110,400
Aggregate unpaid principal balance	431,955	114,920
Cumulative fair value adjustments	(24,182)	(4,520)
Fair value of loans held for sale	407,773	110,400
Loans Held For Sale \| 90 or more days past due
Loans
Aggregate unpaid principal balance	1,395	188
Cumulative fair value adjustments	(1,102)	(153)
Fair value of loans held for sale	293	35
Loans Held For Sale \| Fair Value, Measurements, Recurring
Loans
Fair value of loans held for sale	407,773	110,400
Loans Held for Investment
Loans
Beginning	925,938	21,240
Originations and purchases, and additions	4,243	954,086
Principal payments and cash received	(485,043)	(74,393)
Transfers	(195,106)	22,294
Interest income accretion and fair value adjustments recorded in earnings, and change in unrealized gain	12,158	2,711
Ending	262,190	925,938
Loans Held for Investment \| Balance at Fair Value \| Fair Value, Measurements, Recurring \| Off-balance Sheet Loans
Loans
Aggregate unpaid principal balance	281,031	1,002,465
Cumulative fair value adjustments	(18,841)	(76,527)
Fair value of loans held for investment	262,190	925,938
Loans Held for Investment \| Balance at Fair Value \| Fair Value, Measurements, Recurring \| Off-balance Sheet Loans \| 90 or more days past due
Loans
Aggregate unpaid principal balance	3,774	6,345
Cumulative fair value adjustments	(3,037)	(5,158)
Fair value of loans held for investment	$ 737	$ 1,187

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers In (Out) Adjustment

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Financing Receivable Aggregate Unpaid Principal Before Allowance For Credit Loss

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Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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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.

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