Transactions with Parties-in-Interest (Details) - Community Financial System, Inc. 401(k) Employee Stock Ownership Plan - USD ($) |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
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| Transactions with Parties-in-Interest | ||
| Amount paid for record keeping, trustee, and other services | $ 1,532,000 | $ 1,585,000 |
| Fair value of shares | 473,522,228 | 437,038,226 |
| Stable value fund | 30,906,317 | 32,408,933 |
| Trustee | ||
| Transactions with Parties-in-Interest | ||
| Amount paid for record keeping, trustee, and other services | 1,550,000 | 1,453,000 |
| Subsidiary | ||
| Transactions with Parties-in-Interest | ||
| Stable value fund | $ 30,906,317 | $ 32,408,933 |
| Common stock of plan sponsor | Sponsor | ||
| Transactions with Parties-in-Interest | ||
| Number of shares held | 1,451,117 | 1,423,094 |
| Cost of shares | $ 71,398,164 | $ 67,617,950 |
| Fair value of shares | 83,352,180 | 87,776,467 |
| Dividends received | $ 2,610,028 | $ 2,639,309 |
| Number of shares sold | 346,676 | 432,059 |
| Number of shares purchased | 374,699 | 366,107 |
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- Definition The amount of paid for administrative services by the entity. No definition available.
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- Definition Amount of increase in net asset available for benefit from dividend income on investment held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Contract value of investment, excluding plan interest in master trust, held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Includes, but is not limited to, insurance contract meeting fully benefit-responsive investment criteria. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Cost of investment, excluding plan interest in master trust, held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Includes, but is not limited to, derivative, investment measured at net asset value per share as practical expedient, and insurance contract. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Fair value of investment, excluding plan interest in master trust, held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Includes, but is not limited to, derivative, investment measured at net asset value per share as practical expedient, and insurance contract not meeting fully-benefit responsive investment criteria. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Number of shares or units of investment held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Number of shares or units of investment purchased by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Number of shares or units of investment sold by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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