Fair Value Measurement and fair Value of Financial Instruments - Assets Measured on Non-recurring Basis (Detail) - Fair Value, Measurements, Non-recurring - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets:
Impaired loans	$ 4,680	$ 5,789
Loans held for sale	3,098	1,743
Other real estate owned and other repossessed assets	393	563
(Level 1)
Assets:
Impaired loans	0	0
Loans held for sale	0	0
Other real estate owned and other repossessed assets	0	0
(Level 2)
Assets:
Impaired loans	0	0
Loans held for sale	3,098	1,743
Other real estate owned and other repossessed assets	0	0
(Level 3)
Assets:
Impaired loans	4,680	5,789
Loans held for sale	0	0
Other real estate owned and other repossessed assets	$ 393	$ 563