Commitments and Contingent Liabilities - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Commitments And Contingencies Liabilities [Line Items]
Rental expenses	$ 1,600,000	$ 1,400,000	$ 4,900,000	$ 4,200,000
Sublease income	184,000	$ 190,000	549,000	$ 560,000
Minimum rental to be received in future on subleases	$ 808,000		$ 808,000
Sublease contract maturity year			2025
Fixed rate loan commitments maturity year			2050
Variable rate loan commitments maturity year			2048
Maximum
Commitments And Contingencies Liabilities [Line Items]
Commitments to make loans period			90 days
Loan commitments fixed interest rate	18.00%		18.00%
Loan commitments variable interest rate	8.25%		8.25%
Minimum
Commitments And Contingencies Liabilities [Line Items]
Loan commitments fixed interest rate	1.25%		1.25%
Loan commitments variable interest rate	1.25%		1.25%