Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	$ 586,682	$ 582,202
US Government-sponsored Enterprises Debt Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	122,151	106,906
US States and Political Subdivisions Debt Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	128,966	150,266
Residential Mortgage Backed Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	306,958	297,861
Commercial Mortgage Backed Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	21,710	20,584
Corporate Debt Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	6,027	5,840
Mutual Funds and Equity Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	870	745
Fair Value, Inputs, Level 1 [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	870	745
Fair Value, Inputs, Level 1 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	0	0
Fair Value, Inputs, Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	0	0
Fair Value, Inputs, Level 1 [Member] | Residential Mortgage Backed Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	0	0
Fair Value, Inputs, Level 1 [Member] | Commercial Mortgage Backed Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	0	0
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	0	0
Fair Value, Inputs, Level 1 [Member] | Mutual Funds and Equity Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	870	745
Fair Value, Inputs, Level 2 [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	585,812	581,457
Fair Value, Inputs, Level 2 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	122,151	106,906
Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	128,966	150,266
Fair Value, Inputs, Level 2 [Member] | Residential Mortgage Backed Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	306,958	297,861
Fair Value, Inputs, Level 2 [Member] | Commercial Mortgage Backed Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	21,710	20,584
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	6,027	5,840
Fair Value, Inputs, Level 2 [Member] | Mutual Funds and Equity Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | Residential Mortgage Backed Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | Commercial Mortgage Backed Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | Mutual Funds and Equity Securities [Member]
Note 12 - Fair Value Measurements (Details) - Available for Sale Investment Securities Measured at Fair Value on a Recurring Basis [Line Items]
Available for Sale Securities - Estimated Fair Value	$ 0	$ 0