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Note 2 - Securities - Fair Value of Securities Available for Sale and The Related Unrealized Gains and Losses Recognized in Accumulated Comprehensive Income (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Amortized Cost	$ 725,622	$ 560,828
Gross Unrealized Gains	8,825	14,856
Gross Unrealized Losses	(11,820)	(897)
Fair Value	722,627	574,787
US Treasury and Government [Member]
Amortized Cost	2,005	2,007
Gross Unrealized Gains	36	44
Gross Unrealized Losses	0	0
Fair Value	2,041	2,051
US Treasury Securities [Member]
Amortized Cost	11,954	1,996
Gross Unrealized Gains	51	60
Gross Unrealized Losses	(141)	0
Fair Value	11,864	2,056
US States and Political Subdivisions Debt Securities [Member]
Amortized Cost	429,772	307,201
Gross Unrealized Gains	7,209	13,191
Gross Unrealized Losses	(5,506)	(24)
Fair Value	431,475	320,368
Collateralized Mortgage Backed Securities [Member]
Amortized Cost	276,592	246,085
Gross Unrealized Gains	1,495	1,510
Gross Unrealized Losses	(6,164)	(872)
Fair Value	271,923	246,723
Corporate Debt Securities [Member]
Amortized Cost	1,956	2,539
Gross Unrealized Gains	34	51
Gross Unrealized Losses	0	(1)
Fair Value	1,990	2,589
Trust Preferred Securities [Member]
Amortized Cost	1,000	1,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	1,000	1,000
Asset-backed Securities [Member]
Amortized Cost	2,343
Gross Unrealized Gains	0
Gross Unrealized Losses	(9)
Fair Value	$ 2,334	$ 0

X

- Definition

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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