Fair Value Measurements - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Amount of loans recorded under the fair value option that were delinquent or on non-accrual status	$ 0		$ 0		$ 0
Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Swap agreement, measurement input	0.14		0.14
Prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Swap agreement, measurement input	0.04		0.04
Minimum | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases, measurement input	0.10		0.10
Loan servicing rights, measurement input	0.10		0.10
Other real estate owned, measurement input	0.10		0.10
Minimum | Prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan servicing rights, measurement input	0.09		0.09
Maximum | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans and leases, measurement input	0.15		0.15
Loan servicing rights, measurement input	0.15		0.15
Maximum | Prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan servicing rights, measurement input	0.25		0.25
Net (loss) gain on sales of loans and leases | Loans Held for Sale
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net gain from initial measurement of the correspondent lending loans held for sale and subsequent changes in fair value for loans outstanding	$ 31,400,000	$ 12,400,000	$ 79,000,000.0	$ 18,300,000
Nonrecurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liabilities	$ 0		$ 0		$ 0