XML 25 R17.htm IDEA: XBRL DOCUMENT
v3.25.2

Other Assets and Other Liabilities | 6 Months Ended
--- | ---
Jun. 30, 2025
Other Liabilities [Abstract] |
Other Assets and Other Liabilities | (7.) OTHER ASSETS AND OTHER LIABILITIES A summary of other assets and other liabilities as of the dates indicated are as follows (in thousands):
|  | June 30, |  |  | December 31, |
|  | 2025 |  |  | 2024 |
Other Assets: |  |  |  |  |  |
Tax credit investments |  | $ | 66,082 |  |  | $ | 71,861 |
Net deferred tax asset |  |  | 56,461 |  |  |  | 60,885 |
Derivative instruments |  |  | 31,766 |  |  |  | 46,133 |
Operating lease right of use assets |  |  | 29,736 |  |  |  | 30,369 |
Federal Home Loan Bank (“FHLB”) and Federal Reserve Bank (“FRB”) stock |  |  | 20,798 |  |  |  | 18,261 |
Accrued interest receivable |  |  | 24,928 |  |  |  | 23,748 |
Other |  |  | 49,785 |  |  |  | 50,454 |
Total other assets |  | $ | 279,556 |  |  | $ | 301,711 |
Other Liabilities: |  |  |  |  |  |
Collateral on derivative instruments |  | $ | 27,900 |  |  | $ | 45,960 |
Derivative instruments |  |  | 28,490 |  |  |  | 41,410 |
Operating lease right of use obligations |  |  | 32,193 |  |  |  | 32,763 |
Accrued interest expense |  |  | 23,687 |  |  |  | 25,856 |
Other |  |  | 57,854 |  |  |  | 73,539 |
Total other liabilities |  | $ | 170,124 |  |  | $ | 219,528 |
Included in Other Liabilities–Other as of both June 30, 2025 and December 31, 2024 was a $23.0 million accrual for a contingent litigation liability. Refer to Note 13, Commitments and Contingencies, for more information related to this legal proceeding.

X
- Definition The entire disclosure for other assets and other liabilities. + References No definition available. + Details
Name: | fisi_OtherAssetsAndOtherLiabilitiesDisclosureTextBlock
Namespace Prefix: | fisi_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_OtherLiabilitiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration