Commitments and Contingent Liabilities - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Percentage Of Commercial And industrial Loans to Total Loans
Cash Deposit FDIC Insurance Limit	$ 250,000,000		$ 250,000,000
Uninsured deposits at financial institutions	39,500,000		39,500,000		$ 8,700,000
Commitments for loans	580,400,000		580,400,000		491,100,000
Reserve for unfunded loan commitments	380,000,000		380,000,000		$ 305,000,000
Rent and equipment expense	$ 521,000	$ 619,000	1,600,000	$ 1,900,000
Outstanding unfunded commitments for loans fixed rate of interest amount			26,943,000
Outstanding unfunded commitments for loans fixed rate of interest amount			$ 553,500,000