Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Mar. 31, 2016
Retained Earnings [Member]
Common cash dividends declared, dividends per share (in dollars per share)	$ 0.05	$ 0.05
Common Stock [Member]
Proceeds from issuance of common stock, stock options exercised, shares (in shares)	8,027	44,284	20,975	46,020
Restricted stock awards, shares (in shares)	2,000	13,289	500	22,382
Exchange of common stock in connection with stock options exercised and restricted stock vested, shares (in shares)	594	6,772		19,628
Common cash dividends declared, dividends per share (in dollars per share)			$ 0.04	$ 0.04
Proceeds from issuance of common stock, net of issuance costs, shares (in shares)			1,215,000
Proceeds from issuance of common stock, Employee Stock Purchase Plan, shares (in shares)	4,582	3,573	6,982	5,054
Common cash dividends declared, dividends per share (in dollars per share)	$ 0.05		$ 0.04