Note 15 - Stock Repurchase Plan (Details Textual) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 02, 2019	Aug. 01, 2008
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)					1,000,000
Stock Repurchased and Retired During Period, Shares (in shares)	43,458	49,091	58,216
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased (in shares)	657,451			750,000