Fair Value Measurements - Valuation Assumptions (Details)	Sep. 30, 2021	Dec. 31, 2020
Discount rate | In-house valuation of collateral, External pricing model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan measured for impairment, measurement input (percent)		0.30
Discount rate | In-house valuation of collateral, External pricing model | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan measured for impairment, measurement input (percent)	0.10
Discount rate | In-house valuation of collateral, External pricing model | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan measured for impairment, measurement input (percent)	1
Discount rate | Discounted cash flow | Mortgage servicing rights
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing rights, measurement input (percent)	0.08
Discount rate | Discounted cash flow | Mortgage servicing rights | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing rights, measurement input (percent)		0.0000
Discount rate | Discounted cash flow | Mortgage servicing rights | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing rights, measurement input (percent)		0.0775
Discount rate | Discounted cash flow | Commercial servicing rights
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing rights, measurement input (percent)	0.0946	0.0946
Pull through rate | In-house valuation of collateral, External pricing model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Interest rate lock commitment, measurement input (percent)	0.9246	0.9065
Constant prepayment rate | Discounted cash flow | Mortgage servicing rights | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing rights, measurement input (percent)	0.0993	0.0777
Constant prepayment rate | Discounted cash flow | Mortgage servicing rights | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing rights, measurement input (percent)	0.1402	0.1317
Constant prepayment rate | Discounted cash flow | Commercial servicing rights | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing rights, measurement input (percent)	0.0738	0.0738
Constant prepayment rate | Discounted cash flow | Commercial servicing rights | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing rights, measurement input (percent)	0.0994	0.0994