Note 4 - Loans - Average Recorded Investment and Interest Income Recognized on Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Average recorded investment	$ 11,599	$ 17,745
Interest income recognized	78	68
Commercial Portfolio Segment [Member]
Average recorded investment	2,589	3,396
Interest income recognized	21	10
Commercial Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Interest income recognized
Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Average recorded investment	802	2,004
Interest income recognized	11	11
Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Average recorded investment		809
Interest income recognized		2
Residential Portfolio Segment [Member] | Individual Tax Identification Number Loan [Member]
Average recorded investment	7,425	8,272
Interest income recognized	41	40
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Average recorded investment	326	1,728
Interest income recognized
Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Average recorded investment	422	1,361
Interest income recognized	5	5
Consumer Portfolio Segment [Member]
Average recorded investment	35	175
Interest income recognized