Note 18 - Other Post-retirement Benefit Plans (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 31, 2001	Dec. 31, 2019	Dec. 31, 2018
Liability, Other Postretirement Defined Benefit Plan		$ 3,978,000	$ 3,501,000
Bank Owned Life Insurance		$ 24,631,000	$ 19,028,000
Director Retirement Plan [Member]
Other Postretirement Defined Benefit Plan Expected Annual Future Benefit Payments Period	10 years
Minimum [Member]
Other Postretirement Defined Benefit Plan Expected Annual Future Benefit Payments Period		10 years
Maximum [Member]
Other Postretirement Defined Benefit Plan Expected Annual Future Benefit Payments Period		20 years