Fair Values of Assets and Liabilities - Summary of Significant Unobservable Inputs used in Level 3 Assets Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Inputs, Level 3 [Member] - Fair Value, Measurements, Recurring [Member] $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Mortgage servicing rights [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights	[1]	$ 308	$ 339	$ 350	$ 357
Prepayment Rate [Member] | Mortgage servicing rights [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing Asset, Valuation Technique [Extensible List]		us-gaap:ValuationTechniqueDiscountedCashFlowMember	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Mortgage Servicing Rights		$ 308	$ 339
Prepayment Rate [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights, Measuring Inputs		0.0516	0.0535
Prepayment Rate [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights, Measuring Inputs		0.3148	0.2053
Prepayment Rate [Member] | Weighted Average [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights, Measuring Inputs	[2]	0.0758	0.0685
Fair value valuation techniques		Prepayment Rate	Prepayment Rate
Discount Rate [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights, Measuring Inputs		0.09125	0.09375
Discount Rate [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights, Measuring Inputs		0.09125	0.09375
Discount Rate [Member] | Weighted Average [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights, Measuring Inputs	[2]	0.0913	0.0938
Fair value valuation techniques		Discount Rate	Discount Rate
Delinquency Rate [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights, Measuring Inputs		0.0222	0.0208
Delinquency Rate [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights, Measuring Inputs		0.0279	0.026
Delinquency Rate [Member] | Weighted Average [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights, Measuring Inputs	[2]	0.0232	0.0217
Fair value valuation techniques		Delinquency Rate	Delinquency Rate
Default Rate [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights, Measuring Inputs		0.0014	0.0012
Default Rate [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights, Measuring Inputs		0.0014	0.0014
Default Rate [Member] | Weighted Average [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage Servicing Rights, Measuring Inputs	[2]	0.0014	0.0014
Fair value valuation techniques		Default Rate	Default Rate

[1] Realized and unrealized gains and losses related to mortgage servicing rights are reported as a component of loan servicing fee income in the Company’s consolidated statements of income (loss).

[2] Unobservable inputs for mortgage servicing rights were weighted by loan amount.