Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Available-for-sale, amortized cost	$ 361,297	$ 380,440
Investment equity securities, cost	$ 10,232	$ 5,296
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)	3,636,566	3,612,677
Common stock, shares outstanding (in shares)	3,471,997	3,448,108
Treasury stock, shares (in shares)	164,569	164,569