Short-Term Debt - Mortgage Loan Participation and Sale Agreement (Details)	3 Months Ended
Mar. 31, 2025 USD ($) item	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)
Carrying value:
Loans held for sale	$ 7,095,270,000		$ 8,217,468,000
Mortgage loan participation and sale agreement secured by mortgage loan participation certificates	$ 510,141,000		496,512,000
Mortgage Loan Participation and Sale Agreement member
Short-Term Debt [Line Items]
Number of borrowing facilities secured by loans held for sale \| item	2
During the year:
Short-Term Debt, Average Outstanding Amount	$ 261,045,000	$ 234,874,000
Weighted-average interest rate	5.64%	6.69%
Total interest expense	$ 3,804,000	$ 4,077,000
Carrying value:
Amortization of debt issuance costs	172,000	172,000
Mortgage Loan Participation and Sale Agreement member \| Maximum
Carrying value:
Mortgage loan participation and sale agreement secured by mortgage loan participation certificates	511,846,000	515,990,000
Note Payable
Carrying value:
Unamortized debt issuance costs	(5,392,000)		(6,028,000)
Amortization of debt issuance costs	513,000	$ 750,000
Mortgage Loan Participation and Sale Agreement member
Carrying value:
Unpaid principal balance of mortgage loan participation and sale agreement secured by mortgage loan participation certificates	510,313,000		496,856,000
Unamortized debt issuance costs	(172,000)		(344,000)
Mortgage loan participation and sale agreement secured by mortgage loan participation certificates	$ 510,141,000		$ 496,512,000
Weighted average interest rate	5.58%		5.58%
Asset Pledged as Collateral without Right
Carrying value:
Loans held for sale	$ 7,027,759,000		$ 8,140,834,000
Asset Pledged as Collateral without Right \| Mortgage Loan Participation and Sale Agreement member
Carrying value:
Loans held for sale	$ 542,613,000		$ 528,002,000

Represents the interest expense related to mortgage loans participation and sale agreement.

No definition available.

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- Definition

Participation certificates in mortgage loans that have been pooled with Fannie Mae, Freddie Mac or Ginnie Mae, are issued to a lender pending the securitization of the mortgage loans and sale of the resulting securities.

+ References

No definition available.

+ Details

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- Definition

Amount of unpaid principal balance of mortgage loan participation and sale agreement

+ References

No definition available.

+ Details

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- Definition

+ References

No definition available.

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- References

No definition available.

+ Details

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- References

No definition available.

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- Definition

The number of borrowing facilities secured by loans held for sale.

+ References

No definition available.

+ Details

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- Definition

Amount of amortization expense attributable to debt issuance costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(8))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
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-Name Accounting Standards Codification
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-Publisher FASB
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Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-3

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- Definition

Fair value portion of mortgage loans held-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

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Period Type:	instant

- 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

Weighted average interest rate of short-term debt outstanding calculated at point in time.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-7

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
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-Name Accounting Standards Codification
-Section S99
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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- Definition

Weighted average interest rate of short-term debt outstanding calculated over time.

+ References

No definition available.

+ Details

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- Definition

For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1402
-Paragraph a
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1402
-Paragraph b
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(3))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

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- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

No definition available.

+ Details

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