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Note 2 - Securities - Available-for-sale Securities (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Securities available for sale, amortized cost	$ 504,219,000	$ 380,403,000
Securities available for sale, gross unrealized gains	6,353,000	7,843,000
Securities available for sale, gross unrealized losses	(4,447,000)	(899,000)
Securities available for sale, fair value	506,125,000	387,347,000
US Government Agencies Debt Securities [Member]
Securities available for sale, amortized cost	323,641,000	242,522,000
Securities available for sale, gross unrealized gains	423,000	516,000
Securities available for sale, gross unrealized losses	(3,923,000)	(897,000)
Securities available for sale, fair value	320,141,000	242,141,000
Collateralized Mortgage Backed Securities [Member]
Securities available for sale, amortized cost	36,803,000	23,869,000
Securities available for sale, gross unrealized gains	813,000	1,021,000
Securities available for sale, gross unrealized losses	(297,000)	0
Securities available for sale, fair value	37,319,000	24,890,000
Municipal General Obligation Bonds [Member]
Securities available for sale, amortized cost	124,808,000	101,991,000
Securities available for sale, gross unrealized gains	4,754,000	5,833,000
Securities available for sale, gross unrealized losses	(127,000)	0
Securities available for sale, fair value	129,435,000	107,824,000
Municipal Revenue Bonds [Member]
Securities available for sale, amortized cost	18,467,000	11,521,000
Securities available for sale, gross unrealized gains	363,000	473,000
Securities available for sale, gross unrealized losses	(100,000)	(2,000)
Securities available for sale, fair value	18,730,000	11,992,000
Other Debt and Equity Securities [Member]
Securities available for sale, amortized cost	500,000	500,000
Securities available for sale, gross unrealized gains	0	0
Securities available for sale, gross unrealized losses	0	0
Securities available for sale, fair value	$ 500,000	$ 500,000

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).

+ References

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- Definition

Amount, before tax, of unrealized loss 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).

+ References

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- Definition

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
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-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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