INVESTMENT SECURITIES - Schedule of Amortized Cost and Fair Value Held-to-Maturity (Details) - USD ($) $ in Thousands |
Sep. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Held-to-Maturity | ||
| Allowance for securities held-to-maturity | $ (150) | $ (150) |
| Total held-to-maturity securities | 2,822,927 | 2,895,488 |
| Unrealized Gains | 0 | 853 |
| Unrealized Losses | (559,030) | (356,103) |
| Fair Value | 2,263,897 | 2,540,238 |
| U.S. government-sponsored entities and agencies | ||
| Held-to-Maturity | ||
| Amortized Cost | 827,022 | 840,435 |
| Unrealized Gains | 0 | 0 |
| Unrealized Losses | (180,529) | (129,526) |
| Fair Value | 646,493 | 710,909 |
| Mortgage-backed securities - Agency | ||
| Held-to-Maturity | ||
| Amortized Cost | 859,434 | 910,323 |
| Unrealized Gains | 0 | 0 |
| Unrealized Losses | (168,520) | (127,505) |
| Fair Value | 690,914 | 782,818 |
| States and political subdivisions | ||
| Held-to-Maturity | ||
| Amortized Cost | 1,136,621 | 1,144,880 |
| Unrealized Gains | 0 | 853 |
| Unrealized Losses | (209,981) | (99,072) |
| Fair Value | $ 926,640 | $ 1,046,661 |
| X | ||||||||||
- Definition Amount, excluding accrued interest, of allowance for credit loss on investment in debt security measured at amortized cost (held-to-maturity). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount excluding accrued interest, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity). Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
|
| X | ||||||||||
- Definition Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity). Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|