Note 17 - Assets and Liabilities Measured and Reported at Fair Value (Details Textual) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure	$ 0	$ 0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Impaired Loans [Member] | Appraisal Discount Method [Member]
Assets, Fair Value Disclosure	1,099,000
Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure	568,589,000	566,337,000
Mortgage Servicing Rights [Member]
Impaired Financing Receivable, Related Allowance	0	0
Impaired Loans [Member] | Appraisal Discount Method [Member]
Assets, Fair Value Disclosure	1,100,000	2,100,000
Impaired Financing Receivable, Related Allowance	356,000	544,000
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,455,000	2,602,000
Other Real Estate, Foreclosed Assets, and Repossessed Assets	$ 5,100,000	$ 4,500,000