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v3.25.1

INVESTMENT SECURITIES (Tables) | 3 Months Ended
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Mar. 31, 2025
INVESTMENT SECURITIES |
Schedule of amortized cost and estimated fair value of investment securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | March 31, 2025 | ​ | December 31, 2024
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
(000’s omitted) |  | Cost |  | Gains |  | Losses |  | Value |  | Cost |  | Gains |  | Losses |  | Value
Available-for-Sale Portfolio: | ​ | ​ | ​ |  | ​ |  |  | ​ |  | ​ | ​ | ​ | ​ | ​ | ​ |  | ​ |  |  | ​ |  | ​ | ​ | ​
U.S. Treasury and agency securities | ​ | $ | 2,391,650 | ​ | $ | 0 | ​ | $ | 256,733 | ​ | $ | 2,134,917 | ​ | $ | 2,389,208 | ​ | $ | 0 | ​ | $ | 305,422 | ​ | $ | 2,083,786
Obligations of state and political subdivisions | ​ |  | 424,482 | ​ |  | 264 | ​ |  | 46,260 | ​ |  | 378,486 | ​ |  | 428,204 | ​ |  | 288 | ​ |  | 41,997 | ​ |  | 386,495
Government agency mortgage-backed securities | ​ |  | 351,913 | ​ |  | 56 | ​ |  | 52,178 | ​ |  | 299,791 | ​ |  | 360,102 | ​ |  | 37 | ​ |  | 58,915 | ​ |  | 301,224
Corporate debt securities | ​ |  | 8,000 | ​ |  | 0 | ​ |  | 229 | ​ |  | 7,771 | ​ |  | 8,000 | ​ |  | 0 | ​ |  | 303 | ​ |  | 7,697
Government agency collateralized mortgage obligations | ​ |  | 6,244 | ​ |  | 0 | ​ |  | 294 | ​ |  | 5,950 | ​ |  | 6,878 | ​ |  | 0 | ​ |  | 366 | ​ |  | 6,512
Total available-for-sale portfolio | ​ | $ | 3,182,289 | ​ | $ | 320 | ​ | $ | 355,694 | ​ | $ | 2,826,915 | ​ | $ | 3,192,392 | ​ | $ | 325 | ​ | $ | 407,003 | ​ | $ | 2,785,714
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Held-to-Maturity Portfolio: | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury and agency securities | ​ | $ | 1,146,066 | ​ | $ | 0 | ​ | $ | 87,496 | ​ | $ | 1,058,570 | ​ | $ | 1,138,743 | ​ | $ | 0 | ​ | $ | 123,194 | ​ | $ | 1,015,549
Government agency mortgage-backed securities | ​ | ​ | 247,771 | ​ | ​ | 1,051 | ​ | ​ | 1,004 | ​ | ​ | 247,818 | ​ | ​ | 206,412 | ​ | ​ | 448 | ​ | ​ | 2,241 | ​ | ​ | 204,619
Total held-to-maturity portfolio | ​ | $ | 1,393,837 | ​ | $ | 1,051 | ​ | $ | 88,500 | ​ | $ | 1,306,388 | ​ | $ | 1,345,155 | ​ | $ | 448 | ​ | $ | 125,435 | ​ | $ | 1,220,168
Schedule of gains and losses on equity and other securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Three Months Ended
​ | ​ | March 31,
(000’s omitted) |  | 2025 |  | 2024
Net gain recognized on equity securities | ​ | $ | 245 | ​ | $ | 16
Less: Net gain (loss) recognized on equity securities sold during the period | ​ |  | 0 | ​ |  | 0
Unrealized gain recognized on equity securities still held | ​ | $ | 245 | ​ | $ | 16
Schedule of investment securities that have been in a continuous unrealized loss position | As of March 31, 2025 ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Less than 12 Months |  | 12 Months or Longer |  | Total
​ | ​ | ​ | ​ | ​ | Gross | ​ | ​ | ​ | ​ | Gross | ​ | ​ | ​ | ​ | Gross
​ | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized
(000’s omitted) |  | Value |  | Losses |  | Value |  | Losses |  | Value |  | Losses
Available-for-Sale Portfolio: | ​ | ​ |  | ​ | ​ |  | ​ | ​ |  | ​ | ​ |  | ​ | ​ | ​ | ​ | ​ |
U.S. Treasury and agency securities | ​ | $ | 0 | ​ | $ | 0 | ​ | $ | 2,134,917 | ​ | $ | 256,733 | ​ | $ | 2,134,917 | ​ | $ | 256,733
Obligations of state and political subdivisions | ​ |  | 52,985 | ​ |  | 1,954 | ​ |  | 295,396 | ​ |  | 44,306 | ​ |  | 348,381 | ​ |  | 46,260
Government agency mortgage-backed securities | ​ |  | 6,722 | ​ |  | 122 | ​ |  | 289,643 | ​ |  | 52,056 | ​ |  | 296,365 | ​ |  | 52,178
Corporate debt securities | ​ | ​ | 0 | ​ | ​ | 0 | ​ | ​ | 7,771 | ​ | ​ | 229 | ​ | ​ | 7,771 | ​ | ​ | 229
Government agency collateralized mortgage obligations | ​ |  | 0 | ​ |  | 0 | ​ |  | 5,941 | ​ |  | 294 | ​ |  | 5,941 | ​ |  | 294
Total available-for-sale investment portfolio | ​ | $ | 59,707 | ​ | $ | 2,076 | ​ | $ | 2,733,668 | ​ | $ | 353,618 | ​ | $ | 2,793,375 | ​ | $ | 355,694
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Held-to-Maturity Portfolio: | ​ |  | ​ | ​ |  |  |  |  |  | ​ |  |  |  |  |  | ​ |  | ​
U.S Treasury and agency securities | ​ | $ | 0 | ​ | $ | 0 | ​ | $ | 1,058,570 | ​ | $ | 87,496 | ​ | $ | 1,058,570 | ​ | $ | 87,496
Government agency mortgage-backed securities | ​ | ​ | 116,129 | ​ | ​ | 869 |  | ​ | 21,934 | ​ | ​ | 135 |  | ​ | 138,063 | ​ | ​ | 1,004
Total held-to-maturity portfolio | ​ | $ | 116,129 | ​ | $ | 869 |  | $ | 1,080,504 | ​ | $ | 87,631 |  | $ | 1,196,633 | ​ | $ | 88,500
​ As of December 31, 2024 ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Less than 12 Months |  | 12 Months or Longer |  | Total
​ | ​ | ​ | ​ | ​ | Gross | ​ | ​ | ​ | ​ | Gross | ​ | ​ | ​ | ​ | Gross
​ | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized
(000’s omitted) |  | Value |  | Losses |  | Value |  | Losses |  | Value |  | Losses
Available-for-Sale Portfolio: | ​ | ​ |  | ​ | ​ |  | ​ | ​ |  | ​ | ​ |  | ​ | ​ |  | ​ | ​ |
U.S. Treasury and agency securities | ​ | $ | 0 | ​ | $ | 0 | ​ | $ | 2,083,786 | ​ | $ | 305,422 | ​ | $ | 2,083,786 | ​ | $ | 305,422
Obligations of state and political subdivisions | ​ |  | 47,144 | ​ |  | 847 | ​ |  | 301,202 | ​ |  | 41,150 | ​ |  | 348,346 | ​ |  | 41,997
Government agency mortgage-backed securities | ​ |  | 7,943 | ​ |  | 221 | ​ |  | 290,786 | ​ |  | 58,694 | ​ |  | 298,729 | ​ |  | 58,915
Corporate debt securities | ​ | ​ | 0 | ​ | ​ | 0 | ​ | ​ | 7,697 | ​ | ​ | 303 | ​ | ​ | 7,697 | ​ | ​ | 303
Government agency collateralized mortgage obligations | ​ |  | 0 | ​ |  | 0 | ​ |  | 6,501 | ​ |  | 366 | ​ |  | 6,501 | ​ |  | 366
Total available-for-sale investment portfolio | ​ | $ | 55,087 | ​ | $ | 1,068 | ​ | $ | 2,689,972 | ​ | $ | 405,935 | ​ | $ | 2,745,059 | ​ | $ | 407,003
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Held-to-Maturity Portfolio: | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S Treasury and agency securities | ​ | $ | 0 | ​ | $ | 0 | ​ | $ | 1,015,549 | ​ | $ | 123,194 | ​ | $ | 1,015,549 | ​ | $ | 123,194
Government agency mortgage-backed securities | ​ | ​ | 149,742 | ​ | ​ | 2,027 | ​ | ​ | 15,281 | ​ | ​ | 214 | ​ | ​ | 165,023 | ​ | ​ | 2,241
Total held-to-maturity portfolio | ​ | $ | 149,742 | ​ | $ | 2,027 | ​ | $ | 1,030,830 | ​ | $ | 123,408 | ​ | $ | 1,180,572 | ​ | $ | 125,435
Schedule of amortized cost and estimated fair value of debt securities by contractual maturity | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | Held-to-Maturity | ​ | Available-for-Sale
​ | ​ | Amortized | ​ | Fair | ​ | Amortized | ​ | Fair
(000’s omitted) |  | Cost |  | Value |  | Cost |  | Value
Due in one year or less | ​ | $ | 0 | ​ | $ | 0 | ​ | $ | 15,639 | ​ | $ | 15,619
Due after one through five years | ​ |  | 0 | ​ |  | 0 | ​ | ​ | 1,945,755 | ​ | ​ | 1,814,590
Due after five years through ten years | ​ |  | 569,165 | ​ |  | 547,361 | ​ | ​ | 374,308 | ​ | ​ | 319,808
Due after ten years | ​ |  | 576,901 | ​ |  | 511,209 | ​ | ​ | 488,430 | ​ | ​ | 371,157
Subtotal | ​ |  | 1,146,066 | ​ |  | 1,058,570 | ​ | ​ | 2,824,132 | ​ | ​ | 2,521,174
Government agency mortgage-backed securities | ​ |  | 247,771 | ​ |  | 247,818 | ​ | ​ | 351,913 | ​ | ​ | 299,791
Government agency collateralized mortgage obligations | ​ |  | 0 | ​ |  | 0 | ​ | ​ | 6,244 | ​ | ​ | 5,950
Total | ​ | $ | 1,393,837 | ​ | $ | 1,306,388 | ​ | $ | 3,182,289 | ​ | $ | 2,826,915

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