Derivatives and Risk Management Activities - Schedule of Derivative Instruments (Detail) $ in Thousands	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Matched Interest Rate Swap With Borrower [Member]
Derivative [Line Items]
Notional Amount	$ 210,793	$ 210,314
Positions	40	38
Assets	$ 2,097	$ 12,152
Collateral Pledges	15,120	15,120
Matched Interest Rate Swaps With Counterparty [Member]
Derivative [Line Items]
Notional Amount	$ 210,793	$ 210,314
Positions	40	38
Liabilities	$ 2,097	$ 12,152
Collateral Pledges	$ 15,120	$ 15,120