Note 9 - Income Taxes - Difference Between Financial Statement Tax Expense and Amount Computer by Applying Statutory Federal Tax Rate to Income Before Income Taxes (Details) - USD ($)	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statutory Federal Income Taxes	$ 4,283,394	$ 4,134,570	$ 3,671,971
Tax-Exempt Interest	(109,759)	(83,903)	(74,138)
Premiums on Officers’ Life Insurance	(182,532)	(232,988)	(186,712)
Meal and Entertainment Disallowance	16,813	21,600	14,044
Other	(156,583)	(51,476)	(156,878)
Actual Federal Income Taxes	$ 3,851,333	$ 3,787,803	$ 3,268,287

Amount of current and deferred federal income tax expense (benefit) attributable to income (loss) from continuing operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32672-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Income Tax Expense (or Benefit)
-URI http://asc.fasb.org/extlink&oid=6515339

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(1))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32687-109319

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority noncontrolling interest income (loss), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, increase (decrease) in enacted tax rate, prior year income taxes, increase (decrease) in deferred tax asset valuation allowance, and other adjustments.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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