Goodwill and Other Intangible Assets - Schedule of Other Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Net (Excluding Goodwill)	$ 1,771	$ 2,481
Core deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Net	1,465	2,043
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Net	$ 306	$ 438