SCHEDULE H, LINE 4i - SCHEDULE OF ASSETS (HELD AT END OF YEAR) (Details) - EBP 002
$ in Thousands |
12 Months Ended |
|
Dec. 31, 2025
USD ($)
shares
|
|---|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Plan Name |
FINANCIAL INSTITUTIONS, INC. 401(K) PLAN
|
| Entity Tax Identification Number |
16-0816610
|
| EBP, Plan Number |
002
|
| EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution |
$ 769,666
|
| EBP, Asset Held for Investment, Total |
$ 80,660,168
|
| Investment, Identifier [Axis]: American Funds EuroPacific Growth Fund; Class R-6 |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
American Funds EuroPacific Growth Fund; Class R-6 [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
11,465
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 694,564
|
| Investment, Identifier [Axis]: Baird Core Plus Bond Fund; Institutional Class |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Baird Core Plus Bond Fund; Institutional Class [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
43,920
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 452,813
|
| Investment, Identifier [Axis]: Fidelity Large Cap Growth Index Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Fidelity Large Cap Growth Index Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
58,449
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 2,704,422
|
| Investment, Identifier [Axis]: Financial Institutions, Inc. Company Stock |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Financial Institutions, Inc. Company Stock [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Common Collective Trust [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
69,196
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 2,156,841
|
| Investment, Identifier [Axis]: Putnam Large Cap Value Fund; Class R6 |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Putnam Large Cap Value Fund; Class R6 [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
7,030
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 276,078
|
| Investment, Identifier [Axis]: Vanguard 500 Index Fund Admiral Shares |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard 500 Index Fund Admiral Shares [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
9,284
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 5,866,045
|
| Investment, Identifier [Axis]: Vanguard Emerging Markets Stock Index Fund Admiral Shr |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Emerging Markets Stock Index Fund Admiral Shr [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
20,614
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 919,581
|
| Investment, Identifier [Axis]: Vanguard FTSE All-World ex-US Index Fund Admiral Shares |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard FTSE All-World ex-US Index Fund Admiral Shares [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
2,382
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 108,867
|
| Investment, Identifier [Axis]: Vanguard Federal Money Market Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Federal Money Market Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
us-gaap:CashAndCashEquivalentsAtCarryingValue
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
67,688
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 67,688
|
| Investment, Identifier [Axis]: Vanguard Mid-Cap Index Fund Admiral Shares |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Mid-Cap Index Fund Admiral Shares [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
3,892
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 1,398,684
|
| Investment, Identifier [Axis]: Vanguard Retirement Savings Trust III |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Retirement Savings Trust III [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Common Collective Trust [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
3,939,328
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 3,939,328
|
| Investment, Identifier [Axis]: Vanguard Small-Cap Index Fund Admiral Shares |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Small-Cap Index Fund Admiral Shares [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
11,821
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 1,460,838
|
| Investment, Identifier [Axis]: Vanguard Target Retirement 2020 Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Retirement 2020 Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
116,803
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 3,206,236
|
| Investment, Identifier [Axis]: Vanguard Target Retirement 2025 Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Retirement 2025 Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
431,927
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 8,616,942
|
| Investment, Identifier [Axis]: Vanguard Target Retirement 2030 Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Retirement 2030 Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
253,006
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 10,709,740
|
| Investment, Identifier [Axis]: Vanguard Target Retirement 2035 Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Retirement 2035 Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
452,855
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 12,399,174
|
| Investment, Identifier [Axis]: Vanguard Target Retirement 2040 Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Retirement 2040 Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
127,944
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 6,390,785
|
| Investment, Identifier [Axis]: Vanguard Target Retirement 2045 Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Retirement 2045 Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
173,901
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 6,041,318
|
| Investment, Identifier [Axis]: Vanguard Target Retirement 2050 Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Retirement 2050 Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
78,389
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 4,646,924
|
| Investment, Identifier [Axis]: Vanguard Target Retirement 2055 Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Retirement 2055 Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
35,983
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 2,380,605
|
| Investment, Identifier [Axis]: Vanguard Target Retirement 2060 Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Retirement 2060 Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
21,502
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 1,311,209
|
| Investment, Identifier [Axis]: Vanguard Target Retirement 2065 Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Retirement 2065 Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
8,582
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 343,529
|
| Investment, Identifier [Axis]: Vanguard Target Retirement 2070 Fund |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Retirement 2070 Fund [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
1,281
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 40,762
|
| Investment, Identifier [Axis]: Vanguard Target Retirement Income |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Retirement Income [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
254,541
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 3,530,487
|
| Investment, Identifier [Axis]: Vanguard Total Bond Market Index Fund Admiral Shares |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Total Bond Market Index Fund Admiral Shares [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Funds
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
|
| EBP, Investment, Number of Shares | shares |
23,239
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 227,042
|
| Minimum |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Asset Held for Investment, Participant Loan, Interest Rate |
5.25%
|
| Maximum |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Asset Held for Investment, Participant Loan, Interest Rate |
10.50%
|
| EBP, Asset Held for Investment, Participant Loan, Maturity Date |
Dec. 31, 2039
|
| Mutual Funds |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value |
$ 73,726,645
|