Note 2 - Sales/Mergers/Acquisitions - Changes in Accretable Yield (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Balance at the beginning of the period	$ (6,435)	$ (10,794)	$ (6,471)
Discount added at acquisition			(8,093)
Reclassification of nonaccretable discount to accretable	(353)
Accretion recognized	3,473	4,634	5,132
Balance at the end of the period	(3,139)	(6,435)	(10,794)
Performing Loans
Balance at the beginning of the period	(6,378)	(10,127)	(6,280)
Discount added at acquisition			(7,800)
Reclassification of nonaccretable discount to accretable	(353)
Accretion recognized	2,886	3,749	4,423
Balance at the end of the period	(3,139)	(6,378)	(10,127)
Springfield Bancshares
Balance at the beginning of the period	(3,575)	(6,508)
Discount added at acquisition			(8,093)
Reclassification of nonaccretable discount to accretable	(512)	(159)	(892)
Accretion recognized	2,611	3,092	2,477
Balance at the end of the period	(1,476)	(3,575)	(6,508)
Springfield Bancshares \| Performing Loans
Balance at the beginning of the period	(3,524)	(5,849)
Discount added at acquisition			(7,800)
Accretion recognized	2,048	2,325	1,951
Balance at the end of the period	(1,476)	(3,524)	(5,849)
PCI Loans
Balance at the beginning of the period	(57)	(667)	(191)
Discount added at acquisition			(293)
Accretion recognized	587	885	709
Balance at the end of the period		(57)	(667)
PCI Loans \| Springfield Bancshares
Balance at the beginning of the period	(51)	(659)
Discount added at acquisition			(293)
Reclassification of nonaccretable discount to accretable	(512)	(159)	(892)
Accretion recognized	$ 563	767	526
Balance at the end of the period		$ (51)	$ (659)

The aggregate excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan for loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121585399&loc=d3e13503-111538

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
-Section 50
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- Definition

Current period recognition due to accretion of the excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan for loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
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-Paragraph 2
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- Definition

Increases in the aggregate excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan due to the acquisition of similar loans accounted for as debt securities during the period. This relates to loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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Change in the estimate of cash flows expected to be collected, after acquisition of a loan, which results in an increase in accretable yield (for example, if actual cash flows are significantly greater than previously expected). This relates to loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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