Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Available-for-sale, amortized cost	$ 437,863	$ 349,385
Equity securities, cost	$ 12,726	$ 9,053
Common stock, par value (in dollars per share)	$ 0.625	$ 0.625
Common stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, shares issued (in shares)	3,715,171	3,684,336
Common stock, shares outstanding (in shares)	3,550,602	3,519,767
Treasury stock, shares (in shares)	164,569	164,569