Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Common Stock [Member]
Common shares released from Employee Benefit Trust, shares (in shares)	138,775	116,229
Restricted stock unit awards vested, shares (in shares)	287,155	248,877
Exercise of stock options, shares (in shares)	300
Treasury Stock [Member]
Repurchase of shares to satisfy tax obligation, shares (in shares)	83,908	72,837
Purchase of treasury shares (in shares)		217,863
Retained Earnings [Member]
Dividends on common stock (in dollars per share)	$ 0.21	$ 0.20