Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (Parentheticals) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Common Stock [Member]
Employee stock purchase plan (in shares)	1,053	1,121
Dividend reinvestment plan (in shares)	43,938	44,535
Stock option exercises (in shares)	25,075	50,323
Stock grants to directors (in shares)	11,712	13,000
Share repurchase program (in shares)		167,878
Retained Earnings [Member]
Cash dividends per common share (in dollars per share)	$ 0.55	$ 0.49
Cash dividends per common share (in dollars per share)	$ 0.55	$ 0.49