Fair Value Measurement - Quantitative Information about Recurring Fair Value Measurements (Detail) - Mortgage servicing rights $ in Thousands	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 5,874	$ 5,092	$ 6,200	$ 7,098
Minimum | Constant prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Constant prepayment rate	1.87	2.40
Minimum | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Constant prepayment rate	0.10	0.10
Maximum | Constant prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Constant prepayment rate	2.64	3.33
Maximum | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Constant prepayment rate	0.14	0.14
Weighted Average | Constant prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Constant prepayment rate	2.08	2.94
Weighted Average | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Constant prepayment rate	0.12	0.12