Note 9 - Acquisition of Community State Bank and Common Stock Offering (Details Textual)		1 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	Aug. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2016	Dec. 31, 2015 USD ($)
Community State Bank [Member] | Scenario, Forecast [Member]
Return on Average Assets								1.00%
Community State Bank [Member]
Number of Branches	10
Community State Bank [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Nonaccretable Discount, Accelerated			$ 89,000
Community State Bank [Member] | Ten Branch Locations [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	$ 19,735,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Write-up	$ 8,334,437
Property, Plant and Equipment, Useful Life	39 years
Community State Bank [Member] | Core Deposits [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 6,352,653
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Finite-Lived Intangible Assets, Net		$ 6,291,819	6,291,819			$ 6,291,819
Community State Bank [Member]
Business Acquisition, Percentage of Voting Interests Acquired	100.00%
Business Combination, Consideration Transferred	$ 80,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	581,155,765
Dividends, Cash						15,200,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	20,684,880
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	6,352,653
Business Combination, Acquisition Related Costs		473,000				2,400,000
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual		2,700,000
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual		189,000
Community National Bancorporation and Community National Bank [Member] | Core Deposits [Member]
Finite-Lived Intangible Assets, Net		1,321,774	1,321,774			1,321,774
Revolving Credit Facility [Member]
Proceeds from Lines of Credit	$ 5,000,000					5,000,000
Line of Credit Facility, Maximum Borrowing Capacity		10,000,000	10,000,000	$ 10,000,000		10,000,000			$ 40,000,000
Core Deposits [Member]
Finite-Lived Intangible Assets, Net		6,291,819	6,291,819			6,291,819			6,352,653
Stock Issued During Period, Shares, New Issues | shares				1,215,000
Shares Issued, Price Per Share | $ / shares				$ 24.75
Proceeds from Issuance of Common Stock				$ 29,800,000		1,554,506	$ 1,016,324
Notes Payable		30,000,000	30,000,000			30,000,000
Finite-Lived Intangible Assets, Net		$ 7,613,593	7,613,593		$ 1,521,287	7,613,593	1,521,287		$ 1,471,409
Business Combination, Acquisition Related Costs			$ 2,046,036			$ 2,401,005