FAIR VALUE - Summary of carrying amounts and estimated fair values for financial instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Apr. 02, 2025	Dec. 31, 2024	Sep. 30, 2024	Dec. 31, 2023
Assets:
Cash and cash equivalents	$ 355,639		$ 237,941	$ 278,122	$ 255,192
Held-to-maturity debt securities, net of ACL	93,589		68,161
Loans (includes $4,208 and $7,283 measured at fair value, respectively)	2,590,846		2,425,565
Accrued interest receivable	11,907		10,364
Liabilities:
FHLB borrowings – fixed rate	50,867		57,038
Subordinated notes	44,724		52,565
Accrued interest payable	1,689		1,995
Fair Value Carrying Amount	26,014		32,989
FHLB Advance
Liabilities:
FHLB borrowings – floating rate		$ 50,000
Loans held for investment
Liabilities:
Fair Value Carrying Amount	4,208		7,283
Carrying Amount
Assets:
Cash and cash equivalents	355,639		237,941
Held-to-maturity debt securities, net of ACL	98,205		75,724
Loans (includes $4,208 and $7,283 measured at fair value, respectively)	2,565,671		2,399,952
Accrued interest receivable	11,907		10,364
Liabilities:
Term deposits	349,533		471,415
Non-term deposits	2,499,378		2,042,794
FHLB borrowings – fixed rate			5,000
FHLB borrowings – floating rate			50,000
Federal Reserve borrowings – fixed rate	867		2,038
Accrued interest payable	1,689		1,995
Subordinated Notes | Carrying Amount
Liabilities:
Subordinated notes	44,724		52,565
Quoted Prices in Active Markets for Identical Assets (Level 1) | Estimate of Fair Value Measurement
Assets:
Cash and cash equivalents	355,639		237,941
Held-to-maturity debt securities, net of ACL	248		242
Accrued interest receivable	11,907		10,364
Liabilities:
Term deposits	297,374		429,008
Non-term deposits	2,499,378		2,042,794
FHLB borrowings – fixed rate			5,000
Federal Reserve borrowings – fixed rate	867		2,038
Accrued interest payable	1,689		1,995
Significant Other Observable Inputs (Level 2) | Estimate of Fair Value Measurement
Assets:
Held-to-maturity debt securities, net of ACL	84,784		60,044
Liabilities:
FHLB borrowings – floating rate	50,000		50,000
Significant Unobservable Inputs (Level 3) | Estimate of Fair Value Measurement
Assets:
Held-to-maturity debt securities, net of ACL	8,557		7,875
Loans (includes $4,208 and $7,283 measured at fair value, respectively)	2,510,963		2,325,081
Liabilities:
Term deposits	52,868		42,764
Significant Unobservable Inputs (Level 3) | Subordinated Notes | Estimate of Fair Value Measurement
Liabilities:
Subordinated notes	$ 43,329		$ 48,451