Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) Office Derivative Subsidiary	Dec. 31, 2022 USD ($)	Jan. 01, 2023 USD ($)
Nature of Operations [Abstract]
Specifically-Identified Loan		$ 4,800,000
Transition Charge			$ 1,700,000
Number of wholly-owned subsidiaries | Subsidiary	2
Consolidation of membership interest in Fitzgibbons	100.00%
Number of offices located In Oswego County | Office	7
Number of offices located in Onondaga County | Office	4
Number of loan production office located in Oneida County | Office	1
Significant Group Concentrations of Credit Risk [Abstract]
Minimum commercial real estate loans amount required for additional review	$ 400,000
Advertising Expense [Abstract]
Advertising contracts maturity description	Expenditures for new marketing and advertising material designs and/or media content, related to specifically-identifiable marketing campaigns are capitalized and expensed over the estimated life of the campaign. Such periods of time are generally 12-24 months in duration and do not exceed 36 months.
Cash and Cash Equivalents [Abstract]
Maturity period for classification as cash and cash equivalents, maximum	3 months
Income Recognition on Impaired and Non-accrual Loans [Abstract]
Number of consecutive months of current payments before non-accrual troubled debt restructured loans are restored to accrual status	6 months
Goodwill and Intangible Assets [Abstract]
Estimated useful life	15 years
Interest Rate Derivatives [Member]
Goodwill and Intangible Assets [Abstract]
Number of interest rate derivatives | Derivative	2
Maximum [Member] | Premises [Member]
Premises and Equipment [Abstract]
Useful life	40 years
Maximum [Member] | Equipment [Member]
Premises and Equipment [Abstract]
Useful life	10 years
Commercial Loan
Nature of Operations [Abstract]
Allowance for Loan and Lease Losses	$ 100,000
Residential Loan
Nature of Operations [Abstract]
Allowance for Loan and Lease Losses	$ 300,000
Unfunded Loan Commitment [Member]
Nature of Operations [Abstract]
Actual fundings on lines of credit	5 years
Current Expected Credit Loss [Member]
Nature of Operations [Abstract]
Allowance For Loan And Lease Losses		15,300,000
Specifically-Identified Loan		4,800,000
Aggregate Pool Basis Loan		10,500,000
Transition Charge			1,900,000
Transition Charge Reversed		$ 12,400,000	10,500,000
Historical loss rate			8,400,000
Qualitative factors			4,000,000
Transition Adjustment	$ 1,900,000		2,100,000
Current Expected Credit Loss ACL			$ 12,400,000
Current Expected Credit Loss [Member] | Unfunded Loan Commitment [Member]
Nature of Operations [Abstract]
Created New Reserves	552,000
Current Expected Credit Loss [Member] | Held-to-Maturity Securities [Member]
Nature of Operations [Abstract]
Created New Reserves	$ 450,000
FitzGibbons Agency LLC [Member] | Pathfinder Risk Management Company Inc [Member]
Nature of Operations [Abstract]
Membership interest own in Fitzgibbons through subsidiary	51.00%
Noncontrolling interest by subsidiary	49.00%