Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Additional Paid-in Capital [Member]
Common shares released from Employee Benefit Trust, shares (in shares)	114,754	138,519
Restricted stock unit awards vested, shares (in shares)	284,595	245,311
Exercise of stock options, shares (in shares)	4,400	41,670
Treasury Stock [Member] | Shares Purchased to Fund Options Exercised [Member]
Purchase of treasury shares (in shares)	10,000	378,695
Treasury Stock [Member] | Restricted Stock Awards Repurchased to Satisfy Tax Obligations [Member]
Purchase of treasury shares (in shares)	90,779	77,994
Retained Earnings [Member]
Dividends on common stock (in dollars per share)	$ 0.54	$ 0.51