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Note 2 - Bank Acquisitions (Details Textual) - USD ($) |  |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Oct. 25, 2019 | Sep. 14, 2018 | Mar. 31, 2020 | Dec. 31, 2020 | Dec. 31, 2019
Core Deposits [Member] |  |  |  |  |
Finite-lived Intangible Assets Acquired |  |  |  | $ 0 | $ 1,891,000
Iowa State Savings Bank [Member] |  |  |  |  |
Payments to Acquire Businesses, Gross | $ 22,643,000 |  |  |  |
Goodwill, Acquired During Period | 2,680,000 |  |  |  |
Business Combination, Acquisition Related Costs |  |  |  |  | $ 195,000
Business Combination, Acquired Receivables, Gross Contractual Amount | 139,703,000 |  |  |  |
Business Combination, Deposits, Gross Contractual Amount | 188,068,000 |  |  |  |
Goodwill, Acquired During Period |  |  | $ 310,000 |  |
Iowa State Savings Bank [Member] | Core Deposits [Member] |  |  |  |  |
Finite-lived Intangible Assets Acquired | $ 1,891,000 |  |  |  |
Acquisition of Clarke County State Bank [Member] |  |  |  |  |
Loan Market Valuation Accretion Period (Year) |  | 10 years |  |  |
Time Deposit Market Valuation Period (Year) |  | 2 years |  |  |
Acquisition of Clarke County State Bank [Member] | Core Deposits [Member] |  |  |  |  |
Finite-Lived Intangible Asset, Useful Life (Year) |  | 10 years |  |  |

X
- Definition Represents the gross contractual amount of deposit liabilities acquired in a business combination. + References No definition available. + Details
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- Definition Represents the period over which the loan market valuation is accreted to income on a declining basis. + References No definition available. + Details
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- Definition Period of time for time deposit market valuation to be amortized. + References No definition available. + Details
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X
- Definition For receivables acquired in a business combination, excluding certain loans and debt securities acquired in a transfer (as defined), this element represents the gross contractual amounts receivable, by major class of receivable, such as loans, direct finance leases (as defined), and any other class of receivables. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=121647850&loc=d3e4845-128472 + Details
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X
- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e1043-128460 + Details
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- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275 + Details
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- Definition Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267 + Details
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- Definition Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 16 -URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e961-128460 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267 + Details
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- Definition The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=120321790&loc=d3e6927-128479 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3213-108585 + Details
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