Note 17 - Disclosure of Financial Instruments Not Reported at Fair Value - Financial Assets and Financial Liabilities That Are Not Measured and Reported at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financial assets
Accrued interest receivable	$ 6,865	$ 6,878
Cash and short-term investments	125,125	47,973
Financial liabilities
Accrued interest payable	187	144
Reported Value Measurement [Member]
Financial assets
Federal Home Loan Bank stock and other securities	7,666	6,347
Loans, net	2,284,553	2,281,368
Accrued interest receivable	6,865	6,878
Cash and short-term investments	125,125	47,973
Mortgage loans held for sale	3,055	3,213
Financial liabilities
Deposits	2,478,546	2,520,548
Short-term borrowings	226,487	114,969
FHLB advances	50,433	51,075
Accrued interest payable	187	144
Estimate of Fair Value Measurement [Member]
Financial assets
Federal Home Loan Bank stock and other securities	7,666	6,347
Loans, net	2,290,556	2,284,569
Accrued interest receivable	6,865	6,878
Cash and short-term investments	125,125	47,973
Mortgage loans held for sale	3,121	3,481
Financial liabilities
Deposits	2,477,385	2,519,725
Short-term borrowings	226,487	114,969
FHLB advances	50,531	50,806
Accrued interest payable	187	144
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Financial assets
Federal Home Loan Bank stock and other securities
Loans, net
Accrued interest receivable	6,865	6,878
Cash and short-term investments	125,125	47,973
Mortgage loans held for sale
Financial liabilities
Deposits
Short-term borrowings
FHLB advances
Accrued interest payable	187	144
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Financial assets
Federal Home Loan Bank stock and other securities	7,666	6,347
Loans, net
Accrued interest receivable
Cash and short-term investments
Mortgage loans held for sale	3,121	3,481
Financial liabilities
Deposits
Short-term borrowings	226,487	114,969
FHLB advances	50,531	50,806
Accrued interest payable
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Financial assets
Federal Home Loan Bank stock and other securities
Loans, net	2,290,556	2,284,569
Accrued interest receivable
Cash and short-term investments
Mortgage loans held for sale
Financial liabilities
Deposits	2,477,385	2,519,725
Short-term borrowings
FHLB advances
Accrued interest payable