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)	3 Months Ended		12 Months Ended
	Mar. 31, 2024 USD ($) $ / shares		Dec. 31, 2023 USD ($) $ / shares		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	$ 10,198,000	[1]	$ 11,772,000	[1]	$ 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
Equity Investments [Member] | Precedent Market Transactions [Member] | Equity Method Sale Price [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Sale price	$ 5,084,000
Impaired 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
Impaired 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	0.4351		0.2848
Impaired 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]
Impaired 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	1,800	[4]	2,300	[5]
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	43,200	[4]	45,000	[5]
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	11,290,000		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] | Equity Investments [Member] | Precedent Market Transactions [Member] | Equity Method Sale Price [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity investments	5,084,000
Level 3 [Member] | Impaired 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	21,881,000		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	$ 10,198,000		$ 11,772,000

[1] Includes financed sales of this collateral to third parties that are reported separately from the loan portfolio, of $5.8 million as of March 31, 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.

[5] Relates to the recreation loan portfolio.