Note 12 - Stock Repurchase Program (Details Textual) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Mar. 17, 2020	Dec. 17, 2019	Dec. 18, 2018
Common Stock, Shares, Outstanding, Ending Balance (in shares)	4,223,153	4,323,822
Stock Repurchase Program on December 18, 2018 [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)					300,000
Stock Repurchase Program, Shares Authorized to be Repurchased, Percentage of Stock Outstanding					6.90%
Common Stock, Shares, Outstanding, Ending Balance (in shares)					4,349,624
Treasury Stock, Shares, Acquired (in shares)		54,000
Stock Repurchase Plan on December 17, 2019 [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)			300,000	200,000
Stock Repurchase Program, Shares Authorized to be Repurchased, Percentage of Stock Outstanding				4.60%
Common Stock, Shares, Outstanding, Ending Balance (in shares)				4,323,822
Treasury Stock, Shares, Acquired (in shares)	146,318
Stock Repurchase Plan, Number of Additional Shares Authorized to be Repurchased (in shares)			100,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 2.3