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DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES - Additional information (Details) $ in Thousands	Mar. 31, 2026 USD ($) item	Dec. 31, 2025 USD ($)	Dec. 31, 2019
DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES
Notional amount of interest rate swap	$ 1,238,036	$ 1,203,920
Designated as hedging instrument \| Cash flow hedges
DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES
Notional amount of interest rate swap		50,000
Designated as hedging instrument \| Cash flow hedges \| Interest rate swap on wholesale funding
DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES
Number of instruments \| item	0
Designated as hedging instrument \| Cash flow hedges \| Interest rate swap on variable rate loans
DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES
Number of instruments \| item	0
Variable rate loan assets	$ 50,000
Notional amount of interest rate swap		50,000
Designated as hedging instrument \| Fair Value Hedging
DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES
Notional amount of interest rate swap	37,190	37,190
Designated as hedging instrument \| Fair Value Hedging \| Interest rate swap on deposits
DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES
Notional amount of interest rate swap	$ 37,190	$ 37,190
Fixed interest rate, weighted average			1.696%