Note 9 - Fair Values - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Securities available-for-sale	$ 294,117	$ 256,928
Fair Value, Recurring [Member]
Total assets measured at fair value	294,117	256,928
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Total assets measured at fair value
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Total assets measured at fair value	294,117	256,928
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Total assets measured at fair value
US Government Agencies Debt Securities [Member]
Securities available-for-sale	46,451	40,087
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member]
Securities available-for-sale	46,451	40,087
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	46,451	40,087
US Government Agencies Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale	48,935	50,530
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member]
Securities available-for-sale	48,935	50,530
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	48,935	50,530
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member]
Securities available-for-sale	171,814	138,503
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member]
Securities available-for-sale	171,814	138,503
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	171,814	138,503
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Corporate Debt Securities [Member]
Securities available-for-sale	2,958	2,922
Corporate Debt Securities [Member] | Fair Value, Recurring [Member]
Securities available-for-sale	2,958	2,922
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	2,958	2,922
Corporate Debt Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Commercial Mortgage Backed Securities [Member]
Securities available-for-sale	23,864	24,762
Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
Securities available-for-sale	23,864	24,762
Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	23,864	24,762
Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Asset-backed Securities [Member]
Securities available-for-sale	95	124
Asset-backed Securities [Member] | Fair Value, Recurring [Member]
Securities available-for-sale	95
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale	95
Asset-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale
Other Debt Obligations [Member] | Fair Value, Recurring [Member]
Securities available-for-sale		124
Other Debt Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale
Other Debt Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale		124
Other Debt Obligations [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale