Fair Value Measurement - Schedule of Assets Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2021	Dec. 31, 2020
Fair Value Inputs Asset Quantitative Information [Line Items]
Other real estate owned and repossessed assets	$ 393	$ 549
Fair Value, Measurements, Nonrecurring [Member]
Fair Value Inputs Asset Quantitative Information [Line Items]
Individually-evaluated nonperforming loans	1,909	1,958
Other real estate owned and repossessed assets	393	549
Fair Value, Measurements, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs Asset Quantitative Information [Line Items]
Individually-evaluated nonperforming loans	1,909	1,958
Other real estate owned and repossessed assets	$ 393	$ 549
Individually-evaluated nonperforming loans, Appraisal adjustments	(30.00%)	(30.00%)
Individually-evaluated nonperforming loans, Liquidation expenses	(5.60%)	(5.60%)
Fair Value, Measurements, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Weighted Average [Member]
Fair Value Inputs Asset Quantitative Information [Line Items]
Individually-evaluated nonperforming loans, Appraisal adjustments	(30.00%)	(30.00%)
Individually-evaluated nonperforming loans, Liquidation expenses	(5.60%)	(5.60%)

Carrying amount as of the balance sheet date of other real estate and foreclosed assets. Other real estate may include real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. Foreclosed assets include all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(4))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

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