Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Common Stock [Member]
Common cash dividends declared, dividends per share (in dollars per share)	$ 0.04	$ 0.04	$ 0.04		$ 0.04
Proceeds from issuance of common stock, Employee Stock Purchase Plan, shares (in shares)	4,085	6,982	5,054	5,394	8,558	5,679
Proceeds from issuance of common stock, stock options exercised, shares (in shares)	14,692	20,975	46,020	24,711	17,240	9,688
Exchange of common stock, stock options exercised, shares (in shares)	838		15,689		630
Exchange of common stock, restricted stock vested, shares (in shares)			3,939			3,272
Stock Issued During Period, Shares, New Issues		1,215,000			3,680,000
Retirement of treasury stock, shares (in shares)				121,246
Common cash dividends declared, dividends per share (in dollars per share)	$ 0.04
Stock Issued During Period, Shares, New Issues		1,215,000