Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016
Retained Earnings [Member]
Common cash dividends declared (in dollars per share)	$ 0.05	$ 0.05	$ 0.05
Common Stock [Member]
Common cash dividends declared (in dollars per share)				$ 0.04	$ 0.04	$ 0.04
Proceeds from issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan, shares (in shares)	2,319	4,582	3,573	4,085	6,982	5,054
Proceeds from issuance of common stock, stock options exercised, shares (in shares)	19,906	8,027	44,284	14,692	20,975	46,020
Restricted stock awards - common stock, shares (in shares)	4,500	2,000	13,289		500	22,382
Exchange of common stock, shares (in shares)		594	6,772	838		19,628
Proceeds from issuance of common stock, net of issuance costs, shares (in shares)					1,215,000
Common cash dividends declared (in dollars per share)	$ 0.05			$ 0.04