Consolidated Statements of Changes in Shareholders' Equity (Parentheticals) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Common Stock Including Additional Paid in Capital [Member]
Employee stock purchase plan (in shares)	1,579	1,351	1,362
Dividend reinvestment plan (in shares)	37,450	48,012	58,325
Stock option exercises (in shares)	11,481	28,082	72,711
Stock grants to directors (in shares)	12,404	11,712	13,000
Share repurchase program (in shares)	199,905		167,878
Retained Earnings [Member]
Cash dividends per common share (in dollars per share)	$ 1.68	$ 0.74	$ 1.16