Note 23 - Derivatives and Risk Management Activities - Derivative Instrument Gain (Loss) Recorded in Statement of Income (Details) - Mortgage Banking Income [Member] - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Best Efforts Forward Loan sales Commitments [Member] | Liability Derivatives [Member]
Derivative Gain (Loss), Net	$ 5	$ (45)	$ 32
Mandatory Forward Loan Sales Commitments [Member] | Liability Derivatives [Member]
Derivative Gain (Loss), Net	147	(35)	(157)
Asset Derivatives [Member] | Best Efforts Forward Loan sales Commitments [Member]
Derivative Gain (Loss), Net	(1)		(98)
Asset Derivatives [Member] | Mandatory Forward Loan Sales Commitments [Member]
Derivative Gain (Loss), Net	(8)	(9)	(210)
Asset Derivatives [Member] | Interest Rate Lock Commitments [Member]
Derivative Gain (Loss), Net	(48)	47	(76)
Liability Derivatives [Member] | Interest Rate Lock Commitments [Member] | Liability Derivatives [Member]
Derivative Gain (Loss), Net		$ 1	$ 54