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)		12 Months Ended
		Dec. 31, 2021 USD ($) $ / shares		Dec. 31, 2020 USD ($) $ / shares		Dec. 31, 2019 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Principal portion of loans serviced, fair value		$ 20,500,000		$ 107,100,000
Loan collateral in process of foreclosure		$ 37,430,000	[1]	$ 54,560,000	[1]	$ 52,711,000
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		60	[2]
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		0.0150
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		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
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
Loan Collateral in Process of Foreclosure [Member] | Market Approach [Member] | Historical and Actual Loss Experience [Member] | Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired loans value				1.50
Loan Collateral in Process of Foreclosure [Member] | Market Approach [Member] | Historical and Actual Loss Experience [Member] | Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impaired loans value				6.00
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]	3,600		$ 700
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	[3]	49,800		32,300
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]
Principal portion of loans serviced, fair value	[2]			600
Loan collateral in process of foreclosure value	[2]	0.0		600
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]
Principal portion of loans serviced, fair value	[2]			108,700
Loan collateral in process of foreclosure value	[2]	79,500		108,700
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 securities, fair value		9,453,000				8,291,000
Level 3 [Member] | Equity Investments [Member] | Investee Book Value Adjusted for Market Appreciation [Member] | Equity Method Offering Price [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Equity securities, fair value						$ 1,455,000
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 securities, fair value		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		35,571,000		62,174,000
Level 3 [Member] | Loan Collateral in Process of Foreclosure [Member] | Market Approach [Member] | Measurement Input Median Transfer Price [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan collateral in process of foreclosure				1,432,000
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		$ 37,430,000		$ 53,128,000

[1] Includes financed sales of this collateral to third parties that are reported separately from the loan portfolio, and that are conducted by the Bank of $7.4 million and $3.5 million as of December 31, 2021 and 2020.

[2] Represents amount net of liquidation costs

[3] Relates to the recreation portfolio.