INVESTMENT SECURITIES, Amortized Cost, Unrealized Gains and Losses and Estimated Fair Values of Investments in Debt and Other Securities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Investment securities available-for-sale [Abstract]
Amortized cost	$ 650,058		$ 650,058		$ 683,784
Unrealized gains	16		16		102
Unrealized losses	(62,414)		(62,414)		(65,794)
Estimated fair value	587,660		587,660		618,092
Proceeds from sales of available-for-sale securities	9,785	$ 6,349	16,986	$ 6,349
Gross realized gains from sales of available-for-sale securities	38	0	96	0
Gross realized losses from sales of available-for-sale securities	104	$ 152	160	$ 152
U.S. Treasury Securities [Member]
Investment securities available-for-sale [Abstract]
Amortized cost	115,926		115,926		119,644
Unrealized gains	1		1		13
Unrealized losses	(5,050)		(5,050)		(5,842)
Estimated fair value	110,877		110,877		113,815
Securities of U.S. Government Agencies and Corporations [Member]
Investment securities available-for-sale [Abstract]
Amortized cost	120,835		120,835		128,697
Unrealized gains	0		0		20
Unrealized losses	(8,879)		(8,879)		(9,806)
Estimated fair value	111,956		111,956		118,911
Obligations of States and Political Subdivisions [Member]
Investment securities available-for-sale [Abstract]
Amortized cost	48,924		48,924		58,955
Unrealized gains	2		2		13
Unrealized losses	(4,936)		(4,936)		(5,642)
Estimated fair value	43,990		43,990		53,326
Collateralized Mortgage Obligations [Member]
Investment securities available-for-sale [Abstract]
Amortized cost	113,363		113,363		114,983
Unrealized gains	0		0		0
Unrealized losses	(19,397)		(19,397)		(19,633)
Estimated fair value	93,966		93,966		95,350
Mortgage-backed Securities [Member]
Investment securities available-for-sale [Abstract]
Amortized cost	251,010		251,010		261,505
Unrealized gains	13		13		56
Unrealized losses	(24,152)		(24,152)		(24,871)
Estimated fair value	$ 226,871		$ 226,871		$ 236,690