Note 2 - Common Stock Outstanding and Earnings Per Share (Details Textual) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended
	Jan. 31, 2019	Jan. 31, 2019	Mar. 31, 2019
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	1,834,142		1,834,142
Payments to Acquire Businesses, Gross	$ 15,300
Merchants Holding Company [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares		1,834,142
Payments to Acquire Businesses, Gross		$ 15,300	$ 15,300
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans	85,300	85,300
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deposits	190,200	190,200
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Investment Securities	$ 107,400	$ 107,400
Merchants Holding Company [Member] | Bank of Commerce [Member]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	10.00%	10.00%