Fair Value Measurements - Schedule of Quantitative Information of Assets Measured at Fair Value on Nonrecurring Basis (Detail) - Level III [Member] - Impaired Loans [Member] - Appraisal of Collateral [Member] $ in Thousands	Dec. 31, 2020 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value Estimate	$ 10
Impaired loan, measurement input	(0.10)
Weighted Average [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired loan, measurement input	(0.20)