Derivatives and Hedging Activities - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023 USD ($) Derivative	Dec. 31, 2022 USD ($) Derivative	Dec. 31, 2021 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net gain (loss) on change in fair value	$ (1,399,000)	$ 5,838,000	$ 4,080,000
Collateral posted with market value on liability positions with credit risk-related contingent features	26,000,000
Forward TBA Contracts [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net gain (loss) on change in fair value	$ 530,000	$ 3,211,000	2,796,000
Interest Rate Swaps and Caps [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of interest rate swaps | Derivative	236	159
Aggregate notional amount	$ 1,600,000,000	$ 900,000,000
Income (loss) on derivative instrument not designated hedges	$ 9,000,000	$ 4,400,000	$ 4,500,000
Risk Participation in Agreements [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of interest rate swaps | Derivative	19	16
Aggregate notional amount	$ 197,200,000	$ 187,800,000
Risk Participation out Agreement [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of interest rate swaps | Derivative	5	1
Aggregate notional amount	$ 40,900,000	$ 9,600,000
Other Contract [Member] | Forward TBA Contracts [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Aggregate notional amount	$ 27,000,000	$ 14,500,000