Note 5 - Loans - Non-accrual Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Non-accrual portfolio loans	$ 48,787	$ 49,682	$ 52,130
Non-accrual loans held-for-sale	8,000	7,500	5,944
Total non-accrual loans	56,787	57,182	58,074
Contractual interest due	3,302	3,462	3,997
Nonaccrual Loans [Member]
Contractual interest due	3,254	1,573	5,732
Interest recognized	86	95	119
Net interest foregone	$ 3,168	$ 1,478	$ 5,613