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Mortgage Loans on Real Estate, Repurchase Reserve Liability

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Percent of Total Loan Portfolio, Office Space

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Percentage of Commercial real estate Portfolio, Office Space

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Prior Bankruptcy Recoveries by Plaintiffs

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Standby Letters Of Credit Expire Thereafter

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Standby Letters Of Credit, Financial Guarantees required to perform on

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Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Financial guarantees in connection with standby letters of credit	$ 0	$ 0	$ 0	$ 0
Standby letters of credit expiring within one year	189,200		189,200
Standby letters of credit expiring thereafter	9,300		9,300
Residential mortgage loan repurchase reserve liability	200		200
Loss Contingency Accrual	4,600		4,600
Concentration Risk [Line Items]
GNMA Loans past due by 90 days, but not yet repurchased	700		700
Prior Bankruptcy Recoveries by Plaintiffs	$ 110,000		$ 110,000
Percentage of Commercial real estate Portfolio, Office Space	17.00%		17.00%
Percent of Total Loan Portfolio, Office Space	8.00%		8.00%
Minimum
Concentration Risk [Line Items]
Loss Contingency, Damages Sought, Value			$ 386,200
Maximum
Concentration Risk [Line Items]
Loss Contingency, Damages Sought, Value			$ 429,800
Product Concentration Risk \| Revenue Benchmark \| Real Estate Loans As Part Of Loan Portfolio
Concentration Risk [Line Items]
Concentration risk (as a percent)			75.00%		78.00%