Commitments and Credit Risk - Textual (Details) - USD ($)	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Other Commitments [Line Items]
Outstanding letters of credit	$ 63,604,000	$ 71,074,000
Standby Letters of Credit
Other Commitments [Line Items]
Deferred revenue	$ 0	0
Minimum
Other Commitments [Line Items]
Term of letter of credit	9 months
Maximum
Other Commitments [Line Items]
Term of letter of credit	15 years
Credit card commitments
Other Commitments [Line Items]
Outstanding commitments	$ 676,028,000	634,788,000
Other loan commitments
Other Commitments [Line Items]
Outstanding commitments	$ 2,674,548,000	$ 3,991,931,000