Derivative Financial Instruments - Summary of Notional Balance and Fair Values of Derivatives Outstanding (Detail) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Notional Amount	$ 119,526,000	$ 120,368,000
Derivative Assets	8,084,000	3,535,000
Derivative Liabilities	9,550,000	4,076,000
Cash collateral, Derivative Liabilities	(9,441,000)	(4,186,000)
Netting adjustments, Derivative Assets	15,000	182,000
Netting adjustments, Derivative Liabilities	15,000	182,000
Net amount presented in Balance Sheet, Derivative Assets	8,099,000	3,717,000
Net amount presented in Balance Sheet, Derivative Liabilities	124,000	72,000
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	5,693,000	5,797,000
Derivative Assets		30,000
Derivative Liabilities	588,000	177,000
Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	5,693,000	5,797,000
Derivative Assets		30,000
Derivative Liabilities	588,000	177,000
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	113,833,000	114,571,000
Derivative Assets	8,084,000	3,505,000
Derivative Liabilities	8,962,000	3,899,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	113,833,000	114,571,000
Derivative Assets	8,084,000	3,505,000
Derivative Liabilities	$ 8,962,000	$ 3,899,000