Note 9 - Fair Values - Fair Value of Assets Measured on a Non-recurring Basis (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Collateral Dependent Impaired Loans [Member]
Collateral dependent impaired loans			$ 2,400		$ 2,400
Fair Value, Nonrecurring [Member]
Other real estate owned	[1]	$ 0		$ 0		$ 8
Losses resulting from nonrecurring fair value adjustments		0	145	8	151
Total assets measured at fair value	[1]	0		0		2,763
Collateral dependent impaired loans	[1]					$ 2,755
Fair Value, Nonrecurring [Member] | Collateral Dependent Impaired Loans [Member]
Losses resulting from nonrecurring fair value adjustments			145		145
Fair Value, Nonrecurring [Member] | Other Real Estate Owned [Member]
Losses resulting from nonrecurring fair value adjustments		$ 0	$ 0	$ 8	$ 6

[1] Fair value is presented on a nonrecurring basis - Level 3.