Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Retained Earnings [Member]
Cash dividends declared per common share (in dollars per share)	$ 0.06	$ 0.05
Common Stock [Member]
Issuance of shares as a result of stock purchased under the Employee Stock Purchase Plan (in shares)	2,669	3,573
Issuance of shares of common stock as a result of stock options exercised (in shares)	13,074	44,284
Restricted stock awards (in shares)	6,860	13,289
Exchange of shares of common stock in conncection with stock options exercised and restricted stock vested (in shares)	3,814	6,772
Cash dividends declared per common share (in dollars per share)	$ 0.06	$ 0.05