Note 7 - Loans - Contractual Aging of Nonaccrual Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Nonaccrual loans	$ 10,911	$ 13,404
Non accrual Loans [Member]
Loans current and past due, nonaccrual	5,396	5,802
Nonaccrual loans	10,911	13,404
Non accrual Loans [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Nonaccrual loans	1,086	741
Non accrual Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Nonaccrual loans	$ 4,429	$ 6,861