SECURITIES - Securities Available for Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Amortized cost and estimated fair value of debt securities available-for-sale
Amortized Cost	$ 656,640	$ 669,092
Gross Unrealized Gains	64	81
Gross Unrealized Losses	90,676	85,180
Allowance for Credit Losses	0	0
Estimated Fair Value	566,028	583,993
Amortized Cost
Within one year	8,499
After one, but within five years	97,948
After five, but within ten years	18,076
After ten years	470
Total	124,993
Total	656,640	669,092
Fair Value
Within one year	8,297
After one, but within five years	90,687
After five, but within ten years	14,838
After ten years	417
Total	114,239
Total	566,028	583,993
U.S. Treasury notes and bonds
Amortized cost and estimated fair value of debt securities available-for-sale
Amortized Cost	59,828	59,812
Gross Unrealized Gains	0	0
Gross Unrealized Losses	4,666	4,480
Allowance for Credit Losses	0	0
Estimated Fair Value	55,162	55,332
Amortized Cost
Total	59,828	59,812
Fair Value
Total	55,162	55,332
Mortgage-backed securities, residential
Amortized cost and estimated fair value of debt securities available-for-sale
Amortized Cost	467,125	476,240
Gross Unrealized Gains	7	6
Gross Unrealized Losses	77,425	72,422
Allowance for Credit Losses	0	0
Estimated Fair Value	389,707	403,824
Amortized Cost
Without single maturity date	467,125
Total	467,125	476,240
Fair Value
Without single maturity date	389,707
Total	389,707	403,824
Collateralized mortgage obligations
Amortized Cost
Without single maturity date	0
Fair Value
Without single maturity date	0
Obligations of states and political subdivisions
Amortized cost and estimated fair value of debt securities available-for-sale
Amortized Cost	39,415	39,503
Gross Unrealized Gains	0	0
Gross Unrealized Losses	1,270	817
Allowance for Credit Losses	0	0
Estimated Fair Value	38,145	38,686
Amortized Cost
Total	39,415	39,503
Fair Value
Total	38,145	38,686
Corporate bonds and notes
Amortized cost and estimated fair value of debt securities available-for-sale
Amortized Cost	25,750	25,750
Gross Unrealized Gains	0	0
Gross Unrealized Losses	4,818	5,081
Allowance for Credit Losses	0	0
Estimated Fair Value	20,932	20,669
Amortized Cost
Total	25,750	25,750
Fair Value
Total	20,932	20,669
SBA loan pools
Amortized cost and estimated fair value of debt securities available-for-sale
Amortized Cost	64,522	67,787
Gross Unrealized Gains	57	75
Gross Unrealized Losses	2,497	2,380
Allowance for Credit Losses	0	0
Estimated Fair Value	62,082	65,482
Amortized Cost
Without single maturity date	64,522
Total	64,522	67,787
Fair Value
Without single maturity date	62,082
Total	$ 62,082	$ 65,482