Consolidated Statement of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Common Stock [Member]
Common shares released from Employee Benefit Trust (in shares)	5,015	5,568	138,775	3,899	4,455	116,229
Restricted stock unit awards vested, shares (in shares)	9,284	1,120	287,155	8,720		248,877
Exercise of stock options, shares (in shares)			300		600
Restricted stock unit awards vested, shares (in shares)	9,284	1,120	287,155	8,720		248,877
Treasury Stock [Member]
Repurchase of shares to satisfy tax obligation, shares (in shares)	0	382	83,908	3,343	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	$ 0.21	$ 0.20	$ 0.20	$ 0.20
Purchase of treasury shares (in shares)	40,000