Fair Value of Assets and Liabilities - Summary of Valuation Techniques and Significant Unobservable Inputs Used in Non-Recurring Level 3 Fair Value Measurements of Assets and Liabilities (Detail)		6 Months Ended		12 Months Ended
		Jun. 30, 2024 USD ($) $ / shares		Dec. 31, 2023 USD ($) $ / shares		Mar. 31, 2024 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity investments		$ 1,700,000		$ 1,700,000
Principal portion of loans serviced, fair value		14,000,000		14,000,000
Loan collateral in process of foreclosure		$ 9,359,000	[1]	$ 11,772,000	[1]	$ 10,198,000	$ 16,803,000	$ 20,467,000	$ 21,819,000
Equity Investments [Member] | Precedent Market Transactions [Member] | Equity Method Offering Price [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity Value | $ / shares		$ 8.73		$ 8.73
Nonaccrual Loans [Member] | Market Approach [Member] | Historical and Actual Loss Experience [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired loans value		0		0
Nonaccrual Loans [Member] | Market Approach [Member] | Historical and Actual Loss Experience [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired loans value		0.2306		0.2848
Nonaccrual Loans [Member] | Market Approach [Member] | Measurement Input Transfer Prices [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Principal portion of loans serviced, fair value		$ 0	[2]	$ 0	[3]
Nonaccrual Loans [Member] | Market Approach [Member] | Measurement Input Transfer Prices [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Principal portion of loans serviced, fair value		79,500	[2]	79,500	[3]
Loan Collateral in Process of Foreclosure [Member] | Market Approach [Member] | Collateral Value [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan collateral in process of foreclosure value	[4]	2,500		2,300
Loan Collateral in Process of Foreclosure [Member] | Market Approach [Member] | Collateral Value [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan collateral in process of foreclosure value	[4]	51,300		45,000
Loan Collateral in Process of Foreclosure [Member] | Market Approach [Member] | Measurement Input Transfer Prices [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan collateral in process of foreclosure value		0	[2]	0	[3]
Loan Collateral in Process of Foreclosure [Member] | Market Approach [Member] | Measurement Input Transfer Prices [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan collateral in process of foreclosure value		79,500	[2]	79,500	[3]
Level 3 [Member] | Equity Investments [Member] | Investee Financial Analysis [Member] | Measurement Input Financial Condition and Operational Performance [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity investments		10,522,000		11,157,000
Level 3 [Member] | Equity Investments [Member] | Precedent Market Transactions [Member] | Equity Method Offering Price [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity investments		273,000		273,000
Level 3 [Member] | Nonaccrual Loans [Member] | Market Approach [Member] | Historical and Actual Loss Experience [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Principal portion of loans serviced, fair value		22,248,000		25,974,000
Level 3 [Member] | Loan Collateral in Process of Foreclosure [Member] | Market Approach [Member] | Measurement Input Transfer Prices [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan collateral in process of foreclosure		$ 9,359,000		$ 11,772,000

[1] Includes financed sales of this collateral to third parties that are reported separately from the loan portfolio, of $5.3 million as of June 30, 2024 and $6.2 million as of December 31, 2023.

[2] Represents amount net of liquidation costs.

[3] Represents amount net of liquidation costs.

[4] Relates to the recreation loan portfolio.