Note 2 - Acquisition of Community State Bank and Common Stock Offering (Details Textual)		3 Months Ended	6 Months Ended	12 Months Ended
	Aug. 31, 2016 USD ($)	Jun. 30, 2016 USD ($) $ / shares shares	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
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		$ 2,105,774	$ 1,552,673	$ 620,641
Notes Payable			$ 30,000,000	30,000,000
Business Combination, Acquisition Related Costs				2,441,173
Revolving Credit Facility [Member]
Proceeds from Lines of Credit				5,000,000
Line of Credit Facility, Maximum Borrowing Capacity		$ 10,000,000	10,000,000	10,000,000	$ 40,000,000
Community National Bancorporation and Community National 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	581,000,000
Community State Bank [Member]
Business Combination, Consideration Transferred	80,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	581,676,478
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			11,400,000
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual			$ 2,100,000
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
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] | Land [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Write-up	$ 2,648,208
Community State Bank [Member] | Building [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Write-up	$ 5,686,229
Community State Bank [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Nonaccretable Discount, Accelerated				$ 186,000
Community State Bank [Member]
Number of Branches	10