Note 4 - Share Repurchase Program (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Oct. 31, 2019	Dec. 31, 2018	Nov. 01, 2018
Treasury Stock, Shares, Acquired (in shares)	0	267,300	372,974	105,674
Treasury Stock, Value, Acquired, Cost Method		$ 1,957	$ 2,699	$ 742
Maximum [Member]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)					2,500,000