Commitments and Contingent Liabilities - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) Contract	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Data Processing Contractual Obligations [Abstract]
Number of data processing contractual obligations | Contract	2
Data processing	$ 1,381,000	$ 1,292,000	$ 1,254,000
Cash Segregated under Federal Regulations [Abstract]
Daily average required cash balances with the Federal Reserve Bank	0	0
Core Data Processing [Member]
Data Processing Contractual Obligations [Abstract]
Data processing	1,200,000	1,200,000	1,100,000
Interchange Processing [Member]
Data Processing Contractual Obligations [Abstract]
Net interchange income	$ 1,300,000	$ 1,300,000	$ 1,300,000