FAIR VALUE MEASUREMENTS - Schedule of Fair Value of Financial Assets Measured on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Collateral Pledged
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loan, related allowance	$ 9,100	$ 30,100
Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually assessed loans (collateral-dependent)	112,374	102,580
Foreclosed assets and other real estate owned	1,081	881
Nonrecurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually assessed loans (collateral-dependent)	0	0
Foreclosed assets and other real estate owned	0	0
Nonrecurring \| Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually assessed loans (collateral-dependent)	0	0
Foreclosed assets and other real estate owned	0	0
Nonrecurring \| Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individually assessed loans (collateral-dependent)	112,374	102,580
Foreclosed assets and other real estate owned	$ 1,081	$ 881

SIMMONS FIRST NATIONAL CORP 10-K