Loans and Allowance for Credit Losses on Loans - Aging of Past Due Loans by Class of Loans - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Aging of Past Due Loans by Class of Loans
Past due loans 30 day or greater	$ 9,062	$ 6,229
30 days or greater past due
Aging of Past Due Loans by Class of Loans
Nonaccrual loans	1,732	1,918
Less than 30 days past due
Aging of Past Due Loans by Class of Loans
Nonaccrual loans	$ 2,359
Less than 30 days past due nonaccrual loans held-for-investment		$ 5,870

Amount of financing receivable on nonaccrual status.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5111-111524

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919258-210447

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant