v3.26.1
Description of the Plan - Payments of benefits and plan termination (Details) - Community Financial System, Inc. 401(k) Employee Stock Ownership Plan
12 Months Ended
Dec. 31, 2025
USD ($)
Description of the Plan  
Participant normal retirement age 65 years
Required years of service to be completed by participant for retirement 5 years
Maximum account balance $ 7,000
Minimum account balance $ 1,000
Maximum age of participant for payment deferral 65 years
Percentage of employee contributions as hardship withdrawals 100.00%
Vesting percentage on termination 100.00%