Mortgage Servicing Assets - Schedule of Range and Weighted-Average of Significant Unobservable Inputs (Details) - Discounted cash flow - USD ($)	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020
Commercial Mortgage Backed Securities \| Minimum
Servicing Assets at Fair Value [Line Items]
Expected defaults	1.00%	1.00%
Discount rate	7.64%	7.72%
Escrow earn rate	1.04%	0.92%
Loan assumption rate	0.00%	0.00%
Commercial Mortgage Backed Securities \| Maximum
Servicing Assets at Fair Value [Line Items]
Expected defaults	2.00%	2.00%
Discount rate	10.49%	10.66%
Escrow earn rate	1.37%	1.16%
Loan assumption rate	1.71%	1.78%
Commercial Mortgage Backed Securities \| Weighted Average
Servicing Assets at Fair Value [Line Items]
Expected defaults	1.15%	1.17%
Discount rate	9.31%	9.30%
Escrow earn rate	1.04%	1.05%
Loan assumption rate	1.40%	1.39%
Agency residential mortgage-backed securities \| Minimum
Servicing Assets at Fair Value [Line Items]
Discount rate	7.50%	7.51%
Servicing cost	$ 62.00	$ 62.00
Prepayment speed	8.03%	12.35%
Agency residential mortgage-backed securities \| Maximum
Servicing Assets at Fair Value [Line Items]
Discount rate	8.57%	8.80%
Servicing cost	$ 4,375	$ 5,125
Prepayment speed	48.88%	53.36%
Agency residential mortgage-backed securities \| Weighted Average
Servicing Assets at Fair Value [Line Items]
Discount rate	7.54%	7.57%
Servicing cost	$ 68.15	$ 81.67
Prepayment speed	11.67%	16.89%

Interest rate used to account for mortgage loan at fair value upon assumption.

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- Definition

Servicing Assets And Servicing Liabilities At Fair Value, Assumptions Used To Estimate Fair Value, Escrow Earn Rate

+ References

No definition available.

+ Details

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- Definition

Servicing Assets And Servicing Liabilities At Fair Value, Assumptions Used To Estimate Fair Value, Servicing Cost

+ References

No definition available.

+ Details

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- Definition

Discount rate used to estimate the fair value of servicing assets and servicing liabilities.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=125521744&loc=d3e122596-111746

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- Definition

Percentage of contractually collectible principal associated with a financial asset expected not to be collected due to default by the borrower.

+ References

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- Definition

Estimated rate of prepayments of principal on servicing assets and servicing liabilities.

+ References

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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.

+ Details

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