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)		9 Months Ended		12 Months Ended
		Sep. 30, 2022 USD ($) $ / shares		Dec. 31, 2021 USD ($) $ / shares		Jun. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Principal portion of loans serviced, fair value		$ 19,600,000		$ 20,500,000
Loan collateral in process of foreclosure		$ 24,331,000	[1]	$ 37,430,000	[1]	$ 26,974,000	$ 42,544,000	$ 49,039,000	$ 54,560,000
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
Impaired Loans [Member] | Market Approach [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired loans, balance percentage		0.60		0.60
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		0.0000		0.0150
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		552		0.0600
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	[2]	$ 0.0		$ 0.0
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	[2]	79,500		79,500
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		3,600		3,600	[3]
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		40,100		49,800	[3]
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		0.0	[4]	0.0	[2]
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	[4]	79,500	[2]
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		10,397,000		9,453,000
Level 3 [Member] | Impaired Loans [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] | 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		30,780,000		35,571,000
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		$ 24,331,000		$ 37,430,000

[1] Includes financed sales of this collateral to third parties that are reported separately from the loan portfolio, of $7.8 million as of September 30, 2022 and $7.4 million as of December 31, 2021

[2] Represents amount net of liquidation costs.

[3] Relates to the recreation portfolio.

[4] Represents amount net of liquidation costs.