Note 6 - Securities - Securities Available-for-sale (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Amortized cost	$ 627,380	$ 274,886
Gross unrealized gains	13,583	3,987
Gross unrealized losses	358	680
Fair value	640,605	278,193
US Government Agencies Debt Securities [Member]
Amortized cost	2,567	15,654
Gross unrealized gains	5	303
Gross unrealized losses	0	20
Fair value	2,572	15,937
Corporate Debt Securities [Member]
Amortized cost	38,738	23,774
Gross unrealized gains	380	98
Gross unrealized losses	5	158
Fair value	39,113	23,714
Collateralized Mortgage Backed Securities [Member]
Amortized cost	288,373	137,817
Gross unrealized gains	6,893	2,139
Gross unrealized losses	247	497
Fair value	295,019	139,459
US States and Political Subdivisions Debt Securities [Member]
Amortized cost	296,262	97,641
Gross unrealized gains	6,097	1,447
Gross unrealized losses	106	5
Fair value	302,253	99,083
Other Debt Obligations [Member]
Amortized cost	1,440	0
Gross unrealized gains	208	0
Gross unrealized losses	0	0
Fair value	$ 1,648	$ 0

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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