Derivatives and Hedging Activities - Schedule of Fair Value of Derivative Financial Instruments as well as their Location on Balance Sheet (Detail) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Derivatives Fair Value [Line Items]
Total derivative assets	$ 1,354,000	$ 1,088,000
Total derivative liabilities	1,265,000	1,149,000
Not Designated as Hedging Instrument | Interest Rate Products
Derivatives Fair Value [Line Items]
Notional Amount	66,759,000	66,904,000
Total derivative assets	1,354,000	1,088,000
Total derivative liabilities	$ 1,265,000	$ 1,149,000