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Note 13 - Employee Benefit Plans (Details Textual) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Postretirement Health Coverage [Member] |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total | $ 222,000 | $ 14,000 | $ 12,000
Defined Benefit Plan, Benefit Obligation, Ending Balance | 10,000 | 107,000 |
Deferred Compensation Plan [Member] | Former Directors of Valley Ridge Financial Corp. [Member] |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total | 1,000 | 3,000 | 5,000
Defined Benefit Plan, Benefit Obligation, Ending Balance | 8,000 | 33,000 |
Deferred Compensation Plan [Member] | Four Former Executive Officers of Valley Ridge Financial Corp. [Member] |  |  |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total | 17,000 | 26,000 | 6,000
Defined Benefit Plan, Benefit Obligation, Ending Balance | $ 306,000 | 368,000 |
Defined Benefit Plan, Benefit Obligation, Term (Year) | 15 years |  |
Deferred Compensation Plan [Member] | One Former Executive Officer and One Current Executive Officer of Lakestone [Member] |  |  |
Defined Benefit Plan, Benefit Obligation, Ending Balance | $ 0 | 337,000 |
Defined Benefit Plan, Benefit Obligation, Term (Year) | 15 years |  |
Deferred Compensation Plan [Member] | Minimum [Member] | Former Directors of Valley Ridge Financial Corp. [Member] |  |  |
Interest Rate on Deferred Director Fees | 5.50% |  |
Deferred Compensation Plan [Member] | Maximum [Member] | Former Directors of Valley Ridge Financial Corp. [Member] |  |  |
Interest Rate on Deferred Director Fees | 5.84% |  |
The 401(k) Plan [Member] |  |  |
Defined Contribution Plan, Cost | $ 465,000 | $ 233,000 | $ 207,000

X
- Definition Period of time over which the benefit obligation would be paid, 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 The interest rate on director fees. + References No definition available. + Details
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X
- Definition Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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X
- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2709-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4587-114921 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
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- Details
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