Note 4 - Loans - Newly Restructured Loans and Types of Modifications (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Financing receivable modifications		$ 221	$ 61	$ 1,290
Interest Rate Reduction and Extension of Maturity [Member]
Financing receivable modifications				951
Rate Reduction and Payment Deferral [Member]
Financing receivable modifications			61
Payment Deferral [Member]
Financing receivable modifications				118
Extended Maturity [Member]
Financing receivable modifications		139		139
Principal Forgiveness [Member]
Financing receivable modifications		82		82
Commercial Portfolio Segment [Member]
Financing receivable modifications		139		1,090
Commercial Portfolio Segment [Member] | Interest Rate Reduction and Extension of Maturity [Member]
Financing receivable modifications				951
Commercial Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Financing receivable modifications
Commercial Portfolio Segment [Member] | Payment Deferral [Member]
Financing receivable modifications
Commercial Portfolio Segment [Member] | Extended Maturity [Member]
Financing receivable modifications		139		139
Commercial Portfolio Segment [Member] | Principal Forgiveness [Member]
Financing receivable modifications
Residential Portfolio Segment [Member] | Individual Tax Identification Number Loan [Member] | Real Estate Loan [Member]
Financing receivable modifications		82	61	200
Residential Portfolio Segment [Member] | Interest Rate Reduction and Extension of Maturity [Member] | Individual Tax Identification Number Loan [Member] | Real Estate Loan [Member]
Financing receivable modifications
Residential Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member] | Individual Tax Identification Number Loan [Member] | Real Estate Loan [Member]
Financing receivable modifications			61
Residential Portfolio Segment [Member] | Payment Deferral [Member] | Individual Tax Identification Number Loan [Member] | Real Estate Loan [Member]
Financing receivable modifications				118
Residential Portfolio Segment [Member] | Extended Maturity [Member] | Individual Tax Identification Number Loan [Member] | Real Estate Loan [Member]
Financing receivable modifications
Residential Portfolio Segment [Member] | Principal Forgiveness [Member] | Individual Tax Identification Number Loan [Member] | Real Estate Loan [Member]
Financing receivable modifications		$ 82		$ 82