Loans Receivable - Schedule of Additional Information of Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule Of Financial Receivables [Line Items]
Average Record Investment, with no related allowance recorded	$ 1,766	$ 1,491	$ 1,890	$ 1,499
Interest Income Recognized, with no related allowance recorded	5	10	40	41
Average Record Investment	2,034	1,593	2,057	1,499
Interest Income Recognized	13	10	49	45
Single Family [Member]
Schedule Of Financial Receivables [Line Items]
Average Record Investment, with no related allowance recorded	301	1,491	305	1,499
Interest Income Recognized, with no related allowance recorded	2	10	7	41
Non Owner Occupied [Member]
Schedule Of Financial Receivables [Line Items]
Average Record Investment, with no related allowance recorded	1,097		1,099
Interest Income Recognized, with no related allowance recorded			17
Commercial & Industrial [Member]
Schedule Of Financial Receivables [Line Items]
Average Record Investment, with no related allowance recorded	253		357
Interest Income Recognized, with no related allowance recorded	1		10
Average Record Investment, with an allowance recorded	268	$ 102	167	105
Interest Income Recognized, with an allowance recorded	8		9	$ 4
Secured [Member]
Schedule Of Financial Receivables [Line Items]
Average Record Investment, with no related allowance recorded	115		129
Interest Income Recognized, with no related allowance recorded	$ 2		$ 6

Schedule Of Financial Receivables [Line Items]

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- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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- Definition

Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

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-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

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Amount of interest income, recognized on accrual basis, on financing receivables that are recognized as impaired, for which there is no related allowance for credit losses.

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Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired.

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