Note 4 - Loans - Newly Restructured Loans and Types of Modifications (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Financing receivable modifications	$ 654	$ 125	$ 654	$ 125
Extended Maturity [Member]
Financing receivable modifications	0	86	0	86
Payment Deferral [Member]
Financing receivable modifications	654	39	654	39
Commercial Portfolio Segment [Member]
Financing receivable modifications	0	86	0	86
Commercial Portfolio Segment [Member] | Extended Maturity [Member]
Financing receivable modifications	0	86	0	86
Commercial Portfolio Segment [Member] | Payment Deferral [Member]
Financing receivable modifications	0	0	0	0
Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Financing receivable modifications	654	0	654	0
Commercial Real Estate Portfolio Segment [Member] | Extended Maturity [Member] | Commercial Owner Occupied Loan [Member]
Financing receivable modifications	0	0	0	0
Commercial Real Estate Portfolio Segment [Member] | Payment Deferral [Member] | Commercial Owner Occupied Loan [Member]
Financing receivable modifications	654	0	654	0
Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Financing receivable modifications	0	39	0	39
Residential Portfolio Segment [Member] | Extended Maturity [Member] | Home Equity Loan [Member]
Financing receivable modifications	0	0	0	0
Residential Portfolio Segment [Member] | Payment Deferral [Member] | Home Equity Loan [Member]
Financing receivable modifications	$ 0	$ 39	$ 0	$ 39