Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (Parentheticals) - $ / shares	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Common Stock [Member]
Employee stock purchase plan (in shares)	1,169	1,053
Dividend reinvestment plan (in shares)	14,015	43,938
Stock option exercises (in shares)	8,800	25,075
Stock grants to directors (in shares)	11,171	11,712
Retained Earnings [Member]
Cash dividends per common share (in dollars per share)	$ 0.68	$ 0.55
Cash dividends per common share (in dollars per share)	$ 0.68	$ 0.55

Aggregate dividends paid during the period for each share of common stock outstanding.

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