Loans and Allowance for Credit Losses - Collateral dependent loans and related ACL (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Residential real estate loans
Amortized cost	$ 904
Related allowance for credit losses	232
1- to 4-family residential loans
Amortized cost	904
Related allowance for credit losses	$ 232

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Name:	us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant