Note 20 - Assets and Liabilities Measured and Reported at Fair Value - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Securities available-for-sale, fair value	$ 436,995	$ 574,524
Fair Value, Measurements, Recurring [Member]
Securities available-for-sale, fair value	436,995	574,524
Interest Rate Derivative Assets, at Fair Value	1,035	579
Total assets	438,030	575,103	[1]
Interest rate swaps	543	283	[1]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale, fair value		149,984
Interest Rate Derivative Assets, at Fair Value
Total assets		149,984	[1]
Interest rate swaps			[1]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale, fair value	436,995	424,540
Interest Rate Derivative Assets, at Fair Value	1,035	579
Total assets	438,030	425,119	[1]
Interest rate swaps	543	283	[1]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale, fair value
Interest Rate Derivative Assets, at Fair Value
Total assets	0	0
Interest rate swaps			[1]
US Government-sponsored Enterprises Debt Securities [Member]
Securities available-for-sale, fair value	261,039	213,844
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Securities available-for-sale, fair value	261,039	213,844
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale, fair value
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale, fair value	261,039	213,844
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale, fair value
US Treasury and Government [Member] | Fair Value, Measurements, Recurring [Member]
Securities available-for-sale, fair value		149,984
US Treasury and Government [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale, fair value		149,984
US Treasury and Government [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale, fair value
US Treasury and Government [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale, fair value
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available-for-sale, fair value	146,277	161,507
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Measurements, Recurring [Member]
Securities available-for-sale, fair value	146,277	161,507
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale, fair value
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale, fair value	146,277	161,507
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale, fair value
US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale, fair value	29,679	49,189
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Securities available-for-sale, fair value	29,679	49,189
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale, fair value
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale, fair value	29,679	49,189
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale, fair value

[1] December 31, 2017 fair value balances reflect a correction of incorrectly reported year-end balances in Note 20 of the 2017 Form 10-K, which were presented as $575,079, $425,095, and $259, for total assets, total level 2 assets, and interest rate swap liabilities, respectively.