Note 4 - Derivatives - Amount and Fair Value of Mortgage Banking Derivatives (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Interest Rate Contract [Member]
Derivative, amount	$ 20,422,000	$ 20,981,000
Derivative, fair value	646,000	714,000
Forward Contracts [Member]
Derivative, amount	17,500,000	21,250,000
Derivative, fair value	$ (10,000)	$ (157,000)