INVESTMENT SECURITIES, Amortized Cost, Unrealized Gains and Losses and Estimated Fair Values of Investments in Debt and Other Securities (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Investment securities available-for-sale [Abstract]
Amortized cost	$ 680,766,000		$ 680,766,000		$ 636,092,000
Unrealized gains	3,000		3,000		4,798,000
Unrealized losses	(72,784,000)		(72,784,000)		(8,677,000)
Estimated fair value	607,985,000		607,985,000		632,213,000
Proceeds from sales of available-for-sale securities	0	$ 2,470,000	6,349,000	$ 21,917,000
Gross realized gains from sales of available-for-sale securities	0	0	0	322,000
Gross realized losses from sales of available-for-sale securities	0	$ 20,000	152,000	$ 543,000
U.S. Treasury Securities [Member]
Investment securities available-for-sale [Abstract]
Amortized cost	115,583,000		115,583,000		86,534,000
Unrealized gains	0		0		388,000
Unrealized losses	(6,385,000)		(6,385,000)		(711,000)
Estimated fair value	109,198,000		109,198,000		86,211,000
Securities of U.S. Government Agencies and Corporations [Member]
Investment securities available-for-sale [Abstract]
Amortized cost	120,824,000		120,824,000		104,106,000
Unrealized gains	0		0		330,000
Unrealized losses	(10,457,000)		(10,457,000)		(1,826,000)
Estimated fair value	110,367,000		110,367,000		102,610,000
Obligations of States and Political Subdivisions [Member]
Investment securities available-for-sale [Abstract]
Amortized cost	59,263,000		59,263,000		44,842,000
Unrealized gains	3,000		3,000		1,444,000
Unrealized losses	(7,710,000)		(7,710,000)		(301,000)
Estimated fair value	51,556,000		51,556,000		45,985,000
Collateralized Mortgage Obligations [Member]
Investment securities available-for-sale [Abstract]
Amortized cost	117,695,000		117,695,000		137,872,000
Unrealized gains	0		0		665,000
Unrealized losses	(19,553,000)		(19,553,000)		(2,885,000)
Estimated fair value	98,142,000		98,142,000		135,652,000
Mortgage-backed Securities [Member]
Investment securities available-for-sale [Abstract]
Amortized cost	267,401,000		267,401,000		262,738,000
Unrealized gains	0		0		1,971,000
Unrealized losses	(28,679,000)		(28,679,000)		(2,954,000)
Estimated fair value	$ 238,722,000		$ 238,722,000		$ 261,755,000