Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018
Common Stock [Member]
Common shares released from Employee Benefit Trust, shares (in shares)	5,568	138,775	4,455	116,229
Restricted stock unit awards vested, shares (in shares)	1,120	287,155		248,877
Exercise of stock options, shares (in shares)		300	600
Treasury Stock [Member]
Repurchase of shares to satisfy tax obligation, shares (in shares)	382	83,908	32	72,837
Purchase of treasury shares (in shares)			227,581	217,863
Retained Earnings [Member]
Dividends on common stock (in dollars per share)	$ 0.21	$ 0.21	$ 0.20	$ 0.20