Note 4 - Loans - Loans Modified as TDRs (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017 USD ($)	Jun. 30, 2018	Jun. 30, 2017 USD ($)
Number of contracts	0	11	0	13
Pre-modification outstanding recorded investment		$ 2,441		$ 7,158
Post-modification outstanding recorded investment		2,441		7,158
Forbearance [Member]
Pre-modification outstanding recorded investment		2,353		7,070
Extended Maturity [Member]
Pre-modification outstanding recorded investment		63		63
Extended Maturity and Forbearance [Member]
Pre-modification outstanding recorded investment		$ 25		$ 25
Residential Portfolio Segment [Member]
Number of contracts		1		1
Pre-modification outstanding recorded investment		$ 63		$ 63
Post-modification outstanding recorded investment		63		63
Residential Portfolio Segment [Member] | Forbearance [Member]
Pre-modification outstanding recorded investment		0		$ 0
Residential Portfolio Segment [Member] | Extended Maturity [Member]
Number of contracts				1
Pre-modification outstanding recorded investment		63		$ 63
Residential Portfolio Segment [Member] | Extended Maturity and Forbearance [Member]
Pre-modification outstanding recorded investment		$ 0		$ 0
Commercial Real Estate Portfolio Segment [Member]
Number of contracts		7		8
Pre-modification outstanding recorded investment		$ 1,228		$ 5,250
Post-modification outstanding recorded investment		1,228		$ 5,250
Commercial Real Estate Portfolio Segment [Member] | Forbearance [Member]
Number of contracts				8
Pre-modification outstanding recorded investment		1,228		$ 5,250
Commercial Real Estate Portfolio Segment [Member] | Extended Maturity [Member]
Pre-modification outstanding recorded investment		0		0
Commercial Real Estate Portfolio Segment [Member] | Extended Maturity and Forbearance [Member]
Pre-modification outstanding recorded investment		$ 0		$ 0
Construction, Land Acquisition and Development [Member]
Number of contracts		0		0
Pre-modification outstanding recorded investment		$ 0		$ 0
Post-modification outstanding recorded investment		0		0
Construction, Land Acquisition and Development [Member] | Forbearance [Member]
Pre-modification outstanding recorded investment		0		0
Construction, Land Acquisition and Development [Member] | Extended Maturity [Member]
Pre-modification outstanding recorded investment		0		0
Construction, Land Acquisition and Development [Member] | Extended Maturity and Forbearance [Member]
Pre-modification outstanding recorded investment		$ 0		$ 0
Commercial and Industrial [Member]
Number of contracts		3		4
Pre-modification outstanding recorded investment		$ 1,150		$ 1,845
Post-modification outstanding recorded investment		1,150		$ 1,845
Commercial and Industrial [Member] | Forbearance [Member]
Number of contracts				4
Pre-modification outstanding recorded investment		1,125		$ 1,820
Commercial and Industrial [Member] | Extended Maturity [Member]
Pre-modification outstanding recorded investment		0		0
Commercial and Industrial [Member] | Extended Maturity and Forbearance [Member]
Pre-modification outstanding recorded investment		$ 25		$ 25
Consumer Portfolio Segment [Member]
Number of contracts		0		0
Pre-modification outstanding recorded investment		$ 0		$ 0
Post-modification outstanding recorded investment		0		0
Consumer Portfolio Segment [Member] | Forbearance [Member]
Pre-modification outstanding recorded investment		0		0
Consumer Portfolio Segment [Member] | Extended Maturity [Member]
Pre-modification outstanding recorded investment		0		0
Consumer Portfolio Segment [Member] | Extended Maturity and Forbearance [Member]
Pre-modification outstanding recorded investment		$ 0		$ 0
State and Political Subdivisions [Member]
Number of contracts		0		0
Pre-modification outstanding recorded investment		$ 0		$ 0
Post-modification outstanding recorded investment		0		0
State and Political Subdivisions [Member] | Forbearance [Member]
Pre-modification outstanding recorded investment		0		0
State and Political Subdivisions [Member] | Extended Maturity [Member]
Pre-modification outstanding recorded investment		0		0
State and Political Subdivisions [Member] | Extended Maturity and Forbearance [Member]
Pre-modification outstanding recorded investment		$ 0		$ 0