INVESTMENT SECURITIES (Schedule of Securities with Unrealized Losses) (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023 USD ($) item	Dec. 31, 2022 USD ($) item
Held-to-maturity Securities
Number of securities of one issuer | item	0	0
Impairment loss	$ 0	$ 0
Available-for-sale Securities.
Available-for-sale Securities
Less than 12 Months, Estimated Fair Value	3,204	35,528
Less than 12 Months, Unrealized/Unrecognized Losses	(148)	(2,379)
12 months or more, Estimated Fair Value	406,536	387,125
12 months or more, Unrealized/Unrecognized Losses	(81,330)	(86,828)
Total, Estimated Fair Value	409,740	422,653
Total, Unrealized/Unrecognized Losses	(81,478)	(89,207)
Held-to-maturity Securities
Held-to-maturity Securities
Less than 12 Months, Estimated Fair Value	69,642	194,848
Less than 12 Months, Unrealized/Unrecognized Losses	(2,606)	(23,599)
12 months or more, Estimated Fair Value	366,489	242,442
12 months or more, Unrealized/Unrecognized Losses	(62,788)	(49,536)
Total, Estimated Fair Value	436,131	437,290
Total, Unrealized Losses	(65,394)	(73,135)
U.S. Government agency securities | Available-for-sale Securities.
Available-for-sale Securities
Less than 12 Months, Estimated Fair Value	0	0
Less than 12 Months, Unrealized/Unrecognized Losses	0	0
12 months or more, Estimated Fair Value	60,236	59,372
12 months or more, Unrealized/Unrecognized Losses	(7,760)	(8,624)
Total, Estimated Fair Value	60,236	59,372
Total, Unrealized/Unrecognized Losses	(7,760)	(8,624)
U.S. State and Municipal securities | Available-for-sale Securities.
Available-for-sale Securities
Less than 12 Months, Estimated Fair Value	0	2,546
Less than 12 Months, Unrealized/Unrecognized Losses	0	(527)
12 months or more, Estimated Fair Value	9,537	6,666
12 months or more, Unrealized/Unrecognized Losses	(2,074)	(1,910)
Total, Estimated Fair Value	9,537	9,212
Total, Unrealized/Unrecognized Losses	(2,074)	(2,437)
U.S. State and Municipal securities | Held-to-maturity Securities
Held-to-maturity Securities
Less than 12 Months, Estimated Fair Value	0	13,205
Less than 12 Months, Unrealized/Unrecognized Losses	0	(2,609)
12 months or more, Estimated Fair Value	13,657
12 months or more, Unrealized/Unrecognized Losses	(2,096)
Total, Estimated Fair Value	13,657	13,205
Total, Unrealized Losses	(2,096)	(2,609)
Residential MBS | Available-for-sale Securities.
Available-for-sale Securities
Less than 12 Months, Estimated Fair Value	699	19,576
Less than 12 Months, Unrealized/Unrecognized Losses	(32)	(1,654)
12 months or more, Estimated Fair Value	321,976	305,936
12 months or more, Unrealized/Unrecognized Losses	(69,352)	(74,075)
Total, Estimated Fair Value	322,675	325,512
Total, Unrealized/Unrecognized Losses	(69,384)	(75,729)
Residential MBS | Held-to-maturity Securities
Held-to-maturity Securities
Less than 12 Months, Estimated Fair Value	69,642	162,960
Less than 12 Months, Unrealized/Unrecognized Losses	(2,606)	(19,625)
12 months or more, Estimated Fair Value	317,859	226,661
12 months or more, Unrealized/Unrecognized Losses	(57,696)	(47,402)
Total, Estimated Fair Value	387,501	389,621
Total, Unrealized Losses	(60,302)	(67,027)
Commercial MBS | Available-for-sale Securities.
Available-for-sale Securities
Less than 12 Months, Estimated Fair Value	2,505	13,406
Less than 12 Months, Unrealized/Unrecognized Losses	(116)	(198)
12 months or more, Estimated Fair Value	11,364	11,386
12 months or more, Unrealized/Unrecognized Losses	(1,940)	(2,031)
Total, Estimated Fair Value	13,869	24,792
Total, Unrealized/Unrecognized Losses	(2,056)	(2,229)
Commercial MBS | Held-to-maturity Securities
Held-to-maturity Securities
Less than 12 Months, Estimated Fair Value	0	0
Less than 12 Months, Unrealized/Unrecognized Losses	0	0
12 months or more, Estimated Fair Value	6,964	6,835
12 months or more, Unrealized/Unrecognized Losses	(1,142)	(1,276)
Total, Estimated Fair Value	6,964	6,835
Total, Unrealized Losses	(1,142)	(1,276)
Asset-backed Securities | Available-for-sale Securities.
Available-for-sale Securities
Less than 12 Months, Estimated Fair Value	0	0
Less than 12 Months, Unrealized/Unrecognized Losses	0	0
12 months or more, Estimated Fair Value	3,423	3,765
12 months or more, Unrealized/Unrecognized Losses	(204)	(188)
Total, Estimated Fair Value	3,423	3,765
Total, Unrealized/Unrecognized Losses	(204)	(188)
US Treasury Securities | Held-to-maturity Securities
Held-to-maturity Securities
Less than 12 Months, Estimated Fair Value	0	18,683
Less than 12 Months, Unrealized/Unrecognized Losses	0	(1,365)
12 months or more, Estimated Fair Value	28,009	8,946
12 months or more, Unrealized/Unrecognized Losses	(1,854)	(858)
Total, Estimated Fair Value	28,009	27,629
Total, Unrealized Losses	$ (1,854)	$ (2,223)