SECURITIES - Securities Available for Sale (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Amortized cost and estimated fair value of debt securities available-for-sale
Amortized Cost	$ 729,198,000	$ 795,409,000
Estimated Fair Value	632,589,000	792,026,000
Unrealized Gains	157,000	6,587,000
Unrealized Losses	96,766,000	9,970,000
Amortized Cost
Within one year	2,576,000
After one, but within five years	106,445,000
After five, but within ten years	17,887,000
After ten years	470,000
Total	729,198,000	795,409,000
Fair Value
Within one year	2,537,000
After one, but within five years	97,982,000
After five, but within ten years	15,481,000
After ten years	436,000
Total	632,589,000	792,026,000
Proceeds from sales and calls of securities resulting in gains or losses
Debt securities, gain (loss)	0	0
U.S. treasury notes and bonds
Amortized cost and estimated fair value of debt securities available-for-sale
Amortized Cost	61,800,000	61,084,000
Estimated Fair Value	55,574,000	60,431,000
Unrealized Gains	0	27,000
Unrealized Losses	6,225,000	680,000
Amortized Cost
Total	61,800,000	61,084,000
Fair Value
Total	55,574,000	60,431,000
Mortgage-backed securities, residential
Amortized cost and estimated fair value of debt securities available-for-sale
Amortized Cost	518,838,000	582,060,000
Estimated Fair Value	435,131,000	577,361,000
Unrealized Gains	0	4,032,000
Unrealized Losses	83,707,000	8,731,000
Amortized Cost
Without single maturity date	518,838,000
Total	518,838,000	582,060,000
Fair Value
Without single maturity date	435,131,000
Total	435,131,000	577,361,000
Obligations of states and political subdivisions
Amortized cost and estimated fair value of debt securities available-for-sale
Amortized Cost	39,828,000	40,299,000
Estimated Fair Value	38,892,000	42,303,000
Unrealized Gains	2,000	2,004,000
Unrealized Losses	938,000	0
Amortized Cost
Total	39,828,000	40,299,000
Fair Value
Total	38,892,000	42,303,000
Corporate bonds and notes
Amortized cost and estimated fair value of debt securities available-for-sale
Amortized Cost	25,750,000	22,750,000
Estimated Fair Value	21,970,000	22,848,000
Unrealized Gains	0	180,000
Unrealized Losses	3,780,000	82,000
Amortized Cost
Total	25,750,000	22,750,000
Fair Value
Total	21,970,000	22,848,000
SBA loan pools
Amortized cost and estimated fair value of debt securities available-for-sale
Amortized Cost	82,982,000	89,216,000
Estimated Fair Value	81,022,000	89,083,000
Unrealized Gains	155,000	344,000
Unrealized Losses	2,116,000	477,000
Amortized Cost
Without single maturity date	82,982,000
Total	82,982,000	89,216,000
Fair Value
Without single maturity date	81,022,000
Total	$ 81,022,000	$ 89,083,000