| Off-Balance Sheet Commitments (Tables) | 3 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Mar. 31, 2021 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Risks And Uncertainties [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Distribution of Undisbursed Loan Commitments | The following table shows the distribution of undisbursed loan commitments as of the dates indicated: 
 
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| Allowance for Credit Losses Related to Off-Balance Sheet Items | Activity in the allowance for credit losses related to off-balance sheet items was as follows for the periods indicated: 
 
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- Definition Schedule of distribution of undisbursed loan commitments. No definition available. 
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- References No definition available. 
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- Definition Tabular disclosure of allowance for credit loss on securities borrowed. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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