Note 2 - Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Inputs, Level 1 [Member] | Impaired Loans [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member] | Fair Value, Nonrecurring [Member]
Assets, fair value
Fair Value, Inputs, Level 1 [Member] | Impaired Loans [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Fair Value, Nonrecurring [Member]
Assets, fair value
Fair Value, Inputs, Level 1 [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Recurring [Member]
Assets, fair value
Fair Value, Inputs, Level 1 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Recurring [Member]
Assets, fair value
Fair Value, Inputs, Level 1 [Member] | Other Real Estate Owned [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Fair Value, Nonrecurring [Member]
Assets, fair value
Fair Value, Inputs, Level 1 [Member] | Derivative Financial Instruments, Assets [Member] | Fair Value, Recurring [Member] | Interest Rate Swap [Member]
Assets, fair value
Liabilities, fair value
Fair Value, Inputs, Level 2 [Member] | Impaired Loans [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member] | Fair Value, Nonrecurring [Member]
Assets, fair value
Fair Value, Inputs, Level 2 [Member] | Impaired Loans [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Fair Value, Nonrecurring [Member]
Assets, fair value
Fair Value, Inputs, Level 2 [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Recurring [Member]
Assets, fair value	16,881	16,630
Fair Value, Inputs, Level 2 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Recurring [Member]
Assets, fair value	90,172	85,534
Fair Value, Inputs, Level 2 [Member] | Other Real Estate Owned [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Fair Value, Nonrecurring [Member]
Assets, fair value		228
Fair Value, Inputs, Level 2 [Member] | Derivative Financial Instruments, Assets [Member] | Fair Value, Recurring [Member] | Interest Rate Swap [Member]
Assets, fair value	462	101
Liabilities, fair value	(462)	(101)
Fair Value, Inputs, Level 3 [Member] | Impaired Loans [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member] | Fair Value, Nonrecurring [Member]
Assets, fair value	263	264
Fair Value, Inputs, Level 3 [Member] | Impaired Loans [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Fair Value, Nonrecurring [Member]
Assets, fair value	1,206
Fair Value, Inputs, Level 3 [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Recurring [Member]
Assets, fair value
Fair Value, Inputs, Level 3 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Recurring [Member]
Assets, fair value
Fair Value, Inputs, Level 3 [Member] | Other Real Estate Owned [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Fair Value, Nonrecurring [Member]
Assets, fair value
Fair Value, Inputs, Level 3 [Member] | Derivative Financial Instruments, Assets [Member] | Fair Value, Recurring [Member] | Interest Rate Swap [Member]
Assets, fair value
Liabilities, fair value