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Note 2 - INVESTMENT SECURITIES - Amortized Cost and Fair Value of Investment Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Securities HTM:
Securities HTM, Amortized cost	$ 576,748		$ 587,322
Securities HTM, Allowance for Credit (Losses)	(180)		(180)
Securities HTM, Gross Unrealized Gains	11,351		5,292
Securities HTM, Gross Unrealized (Losses)	(49,075)		(56,798)
Securities HTM, Fair Value	538,844		535,636
Securities AFS:
Securities AFS, Amortized Cost	361,607		400,511
Securities AFS, Allowance for Credit (Losses)	(989)
Securities AFS, Gross Unrealized Gains	147		160
Securities AFS, Gross Unrealized (Losses)	(54,445)		(59,711)
Securities AFS, Fair Value	306,320		340,960
U.S. treasuries and govt. sponsored agency securities
Securities AFS:
Securities AFS, Amortized Cost	21,602		19,745
Securities AFS, Gross Unrealized Gains	14		19
Securities AFS, Gross Unrealized (Losses)	(2,674)		(2,783)
Securities AFS, Fair Value	18,942		16,981
Residential mortgage-backed and related securities
Securities AFS:
Securities AFS, Amortized Cost	68,025		73,438
Securities AFS, Gross Unrealized (Losses)	(7,068)		(7,223)
Securities AFS, Fair Value	60,957		66,215
Municipal securities.
Securities HTM:
Securities HTM, Amortized cost	575,698		586,272
Securities HTM, Allowance for Credit (Losses)	(180)	$ (180)	(180)	$ (198)	$ (198)	$ (198)
Securities HTM, Gross Unrealized Gains	11,351		5,292
Securities HTM, Gross Unrealized (Losses)	(49,054)		(56,798)
Securities HTM, Fair Value	537,815		534,586
Securities AFS:
Securities AFS, Amortized Cost	208,038		239,812
Securities AFS, Gross Unrealized Gains	1		66
Securities AFS, Gross Unrealized (Losses)	(40,129)		(46,700)
Securities AFS, Fair Value	167,910		193,178
Asset-backed securities
Securities AFS:
Securities AFS, Amortized Cost	17,363		18,885
Securities AFS, Gross Unrealized Gains	126		48
Securities AFS, Gross Unrealized (Losses)	(96)		(205)
Securities AFS, Fair Value	17,393		18,728
Other securities
Securities HTM:
Securities HTM, Amortized cost	1,050		1,050
Securities HTM, Gross Unrealized (Losses)	(21)
Securities HTM, Fair Value	1,029		1,050
Securities AFS:
Securities AFS, Amortized Cost	46,579		48,631
Securities AFS, Allowance for Credit (Losses)	(989)
Securities AFS, Gross Unrealized Gains	6		27
Securities AFS, Gross Unrealized (Losses)	(4,478)		(2,800)
Securities AFS, Fair Value	$ 41,118		$ 45,858