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SECURITIES (Tables) | 12 Months Ended
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Dec. 31, 2024
SECURITIES |
Schedule of major categories of securities owned by entity | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2024
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
(In thousands) |  | Cost |  | Gains |  | Losses |  | Value
Securities available-for-sale: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Agency notes | ​ | $ | 10,000 | ​ | ​ | — | ​ | ​ | (393) | ​ | $ | 9,607
Treasury securities | ​ | ​ | — | ​ | ​ | — | ​ | ​ | — | ​ | ​ | —
Corporate securities | ​ |  | 173,972 | ​ | ​ | 755 | ​ | ​ | (10,778) | ​ |  | 163,949
Pass-through mortgage-backed securities ("MBS") issued by government sponsored entities ("GSEs") | ​ |  | 303,303 | ​ | ​ | 30 | ​ | ​ | (3,112) | ​ |  | 300,221
Agency CMOs | ​ |  | 220,314 | ​ | ​ | 16 | ​ | ​ | (28,442) | ​ |  | 191,888
State and municipal obligations | ​ | ​ | 26,545 | ​ | ​ | — | ​ | ​ | (1,517) | ​ | ​ | 25,028
Total securities available-for-sale | ​ | $ | 734,134 | ​ | $ | 801 | ​ | $ | (44,242) | ​ | $ | 690,693
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2024
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrecognized | ​ | Unrecognized | ​ | Fair
(In thousands) |  | Cost |  | Gains |  | Losses |  | Value
Securities held-to-maturity: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Agency notes | ​ | $ | 89,977 | ​ | $ | — | ​ | $ | (10,961) | ​ | $ | 79,016
Corporate securities | ​ | ​ | 13,000 | ​ | ​ | 140 | ​ | ​ | (855) | ​ | ​ | 12,285
Pass-through MBS issued by GSEs | ​ | ​ | 298,697 | ​ | ​ | — | ​ | ​ | (43,716) | ​ | ​ | 254,981
Agency CMOs | ​ |  | 235,665 | ​ |  | 29 | ​ |  | (29,699) | ​ |  | 205,995
Total securities held-to-maturity | ​ | $ | 637,339 | ​ | $ | 169 | ​ | $ | (85,231) | ​ | $ | 552,277
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2023
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
(In thousands) |  | Cost |  | Gains |  | Losses |  | Value
Securities available-for-sale: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Agency notes | ​ | $ | 10,000 | ​ | $ | — | ​ | $ | (629) | ​ | $ | 9,371
Treasury securities | ​ | ​ | 245,877 | ​ | ​ | — | ​ | ​ | (11,687) | ​ | ​ | 234,190
Corporate securities | ​ | ​ | 174,978 | ​ |  | — | ​ |  | (23,808) | ​ |  | 151,170
Pass-through MBS issued by GSEs | ​ |  | 230,253 | ​ |  | 10 | ​ |  | (24,978) | ​ |  | 205,285
Agency CMOs | ​ |  | 305,860 | ​ |  | 46 | ​ |  | (46,491) | ​ |  | 259,415
State and municipal obligations | ​ |  | 28,741 | ​ | ​ | — | ​ | ​ | (1,932) | ​ | ​ | 26,809
Total securities available-for-sale | ​ | $ | 995,709 | ​ | $ | 56 | ​ | $ | (109,525) | ​ | $ | 886,240
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2023
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrecognized | ​ | Unrecognized | ​ | Fair
(In thousands) |  | Cost |  | Gains |  | Losses |  | Value
Securities held-to-maturity: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Agency notes | ​ | $ | 89,563 | ​ | $ | — | ​ | $ | (11,300) | ​ | $ | 78,263
Corporate securities | ​ | ​ | 9,000 | ​ | ​ | — | ​ | ​ | (1,825) | ​ | ​ | 7,175
Pass-through MBS issued by GSEs | ​ | ​ | 279,853 | ​ | ​ | — | ​ | ​ | (37,579) | ​ | ​ | 242,274
Agency CMOs | ​ |  | 216,223 | ​ |  | 16 | ​ |  | (27,021) | ​ |  | 189,218
Total securities held-to-maturity | ​ | $ | 594,639 | ​ | $ | 16 | ​ | $ | (77,725) | ​ | $ | 516,930
Amortized cost and fair value of securities are shown by contractual maturity | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2024
​ | ​ | Amortized | ​ | Fair
(In thousands) | ​ | Cost | ​ | Value
Available-for-sale | ​ | ​ | ​ | ​ | ​ | ​
Within one year | ​ | $ | 6,717 | ​ | $ | 6,597
One to five years | ​ | ​ | 54,401 | ​ | ​ | 50,984
Five to ten years | ​ | ​ | 149,399 | ​ | ​ | 141,003
Beyond ten years | ​ | ​ | — | ​ | ​ | —
Pass-through MBS issued by GSEs and agency CMOs | ​ | ​ | 523,617 | ​ | ​ | 492,109
Total | ​ | $ | 734,134 | ​ | $ | 690,693
​ | ​ | ​ | ​ | ​ | ​ | ​
Held-to-maturity | ​ | ​ | ​ | ​ | ​ | ​
Within one year | ​ | $ | — | ​ | $ | —
One to five years | ​ | ​ | 19,829 | ​ | ​ | 18,598
Five to ten years | ​ | ​ | 83,148 | ​ | ​ | 72,703
Beyond ten years | ​ | ​ | — | ​ | ​ | —
Pass-through MBS issued by GSEs and agency CMOs | ​ | ​ | 534,362 | ​ | ​ | 460,976
Total | ​ | $ | 637,339 | ​ | $ | 552,277
Summary of sale of available-for-sale securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Year Ended December 31,
(In thousands) | ​ | 2024 |  | 2023 |  | 2022
Securities available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Proceeds | ​ | $ | 379,053 | ​ | $ | 77,804 | ​ | $ | —
Gross gains | ​ | ​ | — | ​ | ​ | 130 | ​ | ​ | —
Tax expense on gains | ​ | ​ | — | ​ | ​ | 39 | ​ | ​ | —
Gross losses | ​ | ​ | 42,810 | ​ | ​ | 1,577 | ​ | ​ | —
Tax benefit on losses | ​ | ​ | 13,139 | ​ | ​ | 467 | ​ | ​ | —
Schedule of gross unrealized losses and fair value of investment securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2024
​ | ​ | Less than 12 | ​ | 12 Consecutive | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Consecutive Months | ​ | Months or Longer | ​ | Total
​ | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized
(In thousands) |  | Value |  | Losses |  | Value |  | Losses |  | Value |  | Losses
Securities available-for-sale: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Agency notes | ​ | $ | — | ​ | $ | — | ​ | $ | 9,607 | ​ | $ | 393 | ​ | $ | 9,607 | ​ | $ | 393
Corporate securities | ​ | ​ | 2,925 | ​ | ​ | 16 | ​ | ​ | 141,124 | ​ | ​ | 10,762 | ​ | ​ | 144,049 | ​ | ​ | 10,778
Pass-through MBS issued by GSEs | ​ | ​ | 289,095 | ​ | ​ | 2,170 | ​ | ​ | 6,119 | ​ | ​ | 942 | ​ | ​ | 295,214 | ​ | ​ | 3,112
Agency CMOs | ​ | ​ | 32,101 | ​ | ​ | 357 | ​ | ​ | 154,770 | ​ | ​ | 28,085 | ​ | ​ | 186,871 | ​ | ​ | 28,442
State and municipal obligations | ​ |  | 3,469 | ​ |  | 31 | ​ |  | 21,559 | ​ |  | 1,486 | ​ | ​ | 25,028 | ​ | ​ | 1,517
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2023
​ | ​ | Less than 12 | ​ | 12 Consecutive | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Consecutive Months | ​ | Months or Longer | ​ | Total
​ | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized
(In thousands) |  | Value |  | Losses |  | Value |  | Losses |  | Value |  | Losses
Securities available-for-sale: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Agency Notes | ​ | $ | — | ​ | $ | — | ​ | $ | 9,371 | ​ | $ | 629 | ​ | $ | 9,371 | ​ | $ | 629
Treasury securities | ​ | ​ | — | ​ | ​ | — | ​ | ​ | 234,190 | ​ | ​ | 11,687 | ​ | ​ | 234,190 | ​ | ​ | 11,687
Corporate securities | ​ | ​ | 20,935 | ​ | ​ | 917 | ​ | ​ | 130,235 | ​ | ​ | 22,891 | ​ | ​ | 151,170 | ​ | ​ | 23,808
Pass-through MBS issued by GSEs | ​ | ​ | — | ​ | ​ | — | ​ | ​ | 203,469 | ​ | ​ | 24,978 | ​ | ​ | 203,469 | ​ | ​ | 24,978
Agency CMOs | ​ | ​ | — | ​ | ​ | — | ​ | ​ | 251,900 | ​ | ​ | 46,491 | ​ | ​ | 251,900 | ​ | ​ | 46,491
State and municipal obligations | ​ | ​ | 1,796 | ​ |  | 54 | ​ |  | 21,513 | ​ |  | 1,878 | ​ | ​ | 23,309 | ​ | ​ | 1,932

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