INVESTMENT SECURITIES - Schedule of Held To Maturity Credit Quality Indicator (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Past due held-to-maturity debt securities	$ 979,704	$ 1,015,168
FNMA MBS
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Past due held-to-maturity debt securities	799,548	831,325
FNMA MBS | A+ rated or higher
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Past due held-to-maturity debt securities	0	0
FNMA MBS | Not rated
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Past due held-to-maturity debt securities	799,548	831,325
State and political subdivisions
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Past due held-to-maturity debt securities	180,156	183,843
State and political subdivisions | A+ rated or higher
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Past due held-to-maturity debt securities	180,156	183,843
State and political subdivisions | Not rated
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Past due held-to-maturity debt securities	$ 0	$ 0