Consolidated Statements of Changes in Stockholders' Equity (Parentheticals) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Shares of common stock issued under compensation plans	1,329,957	964,053	944,504
Shares of common stock issued to settle warrants that have reached their expiration		92,998	47,868
Dividends on common stock, per share amount	$ 0.26	$ 0.24	$ 0.22