Note 7 - Fair Value of Financial Instruments - Financial Assets Measured at on a Recurring Basis (Details) - USD ($)	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value	200,396,000		178,145,000
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Obligations [Member]
Investment securities available for sale, at fair value	200,396,000		178,145,000
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value	11,686,000		10,171,000
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member]
Investment securities available for sale, at fair value	11,686,000		10,171,000
Fair Value, Measurements, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value	24,442,000		23,344,000
Fair Value, Measurements, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member]
Investment securities available for sale, at fair value	24,442,000		23,344,000
Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value	42,495,000		51,295,000
Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value	2,933,000		2,834,000
Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Investment securities available for sale, at fair value	45,428,000		54,129,000
Fair Value, Measurements, Recurring [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value	15,717,000		17,005,000
Fair Value, Measurements, Recurring [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | Asset-backed Securities [Member]
Investment securities available for sale, at fair value	15,717,000		17,005,000
Fair Value, Measurements, Recurring [Member] | Collateralized Debt Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | Collateralized Debt Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | Collateralized Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value	1,691,000		1,883,000
Fair Value, Measurements, Recurring [Member] | Collateralized Debt Obligations [Member]
Investment securities available for sale, at fair value	1,691,000		1,883,000
Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value	25,000		118,000
Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value
Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member]
Investment securities available for sale, at fair value	25,000		118,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Interest Rate Lock Commitments [Member]
Derivative Asset
Derivative Liability
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Best Efforts Forward Loan sales Commitments [Member]
Derivative Liability
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Mandatory Forward Loan Sales Commitments [Member]
Derivative Liability
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available for sale, at fair value
Mortgage Loans Held for Sale
SBA Servicing Assets
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Lock Commitments [Member]
Derivative Asset	1,027,000
Derivative Liability	9,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Best Efforts Forward Loan sales Commitments [Member]
Derivative Liability	377,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Mandatory Forward Loan Sales Commitments [Member]
Derivative Liability	294,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available for sale, at fair value	294,761,000		280,078,000
Mortgage Loans Held for Sale	26,865,000
SBA Servicing Assets
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest Rate Lock Commitments [Member]
Derivative Asset
Derivative Liability
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Best Efforts Forward Loan sales Commitments [Member]
Derivative Liability
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Mandatory Forward Loan Sales Commitments [Member]
Derivative Liability
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available for sale, at fair value	4,624,000		4,717,000
Mortgage Loans Held for Sale
SBA Servicing Assets	5,297,000		4,886,000
Fair Value, Measurements, Recurring [Member] | Interest Rate Lock Commitments [Member]
Derivative Asset	1,027,000
Derivative Liability	9,000
Fair Value, Measurements, Recurring [Member] | Best Efforts Forward Loan sales Commitments [Member]
Derivative Liability	377,000
Fair Value, Measurements, Recurring [Member] | Mandatory Forward Loan Sales Commitments [Member]
Derivative Liability	294,000
Fair Value, Measurements, Recurring [Member]
Investment securities available for sale, at fair value	299,385,000		284,795,000
Mortgage Loans Held for Sale	26,865,000
SBA Servicing Assets	5,297,000		4,886,000
Collateralized Mortgage Obligations [Member]
Investment securities available for sale, at fair value	200,396,000		178,145,000
Collateralized Mortgage Backed Securities [Member]
Investment securities available for sale, at fair value	11,686,000		10,171,000
US States and Political Subdivisions Debt Securities [Member]
Investment securities available for sale, at fair value	24,442,000		23,344,000
Corporate Debt Securities [Member]
Investment securities available for sale, at fair value	45,428,000		54,129,000
Asset-backed Securities [Member]
Investment securities available for sale, at fair value	15,717,000		17,005,000
Collateralized Debt Obligations [Member]
Investment securities available for sale, at fair value	1,691,000		1,883,000
Other Debt Obligations [Member]
Investment securities available for sale, at fair value	25,000		118,000
Investment securities available for sale, at fair value	299,385,000		284,795,000
SBA Servicing Assets	$ 5,297,000	$ 5,118,000	$ 4,886,000	$ 4,174,000	$ 4,319,000	$ 4,099,000