Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Retained Earnings [Member]
Common dividends declared, per share (in dollars per share)	$ 0.16	$ 0.14
Additional Paid-in Capital [Member]
Restricted stock awards, shares (in shares)	19,034	12,882
Common stock options exercised, shares (in shares)	1,500
Treasury Stock [Member]
Issuance of treasury stock to 401(k) plan, shares (in shares)	5,243	7,727
Purchase of treasury shares, shares (in shares)	6,800	487,739
Purchase of treasury shares, per share (in dollars per share)	$ 24.07	$ 18.14
Common dividends declared, per share (in dollars per share)	$ 0.16	$ 0.14