Note 8 - Loans (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Impaired Financing Receivable, Recorded Investment, Total	$ 119,631	$ 106,886
Percentage Of Charge Off To Contractual Balances For Impaired Loans	9.10%	9.30%
Financing Receivable, Troubled Debt Restructuring, Subsequent Default	$ 0
Financing Receivable, Troubled Debt Restructuring, Commitment to Lend	$ 0
Minimum [Member]
Period Loan Is In Payment Default	60 days
Maximum [Member]
Period Loan Is In Payment Default	90 days
Nonaccrual Loans [Member]
Impaired Financing Receivable, Recorded Investment, Total	$ 56,700	$ 41,800
Accruing Troubled Debt Restructuring [Member]
Impaired Financing Receivable, Recorded Investment, Total	62,900	65,100
Financing Receivable, Troubled Debt Restructuring	62,900	65,100
Troubled Debt Restructuring, Specific Reserves	1,200	1,500
Non-accruing Troubled Debt Restructuring [Member]
Financing Receivable, Troubled Debt Restructuring	23,300	24,200
Troubled Debt Restructuring, Specific Reserves	$ 56	$ 826