Note 8 - Loans - Impaired Loans and Related Allowance for Credit Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Loans with no related allowance, unpaid principal balance	$ 87,680	$ 95,807
Loans with no related allowance, recorded investment	79,755	88,342
Loans with related allowance, unpaid principal balance	49,604	28,637
Loans with related allowance, recorded investment	47,916	26,732
Allowance	2,606	2,796
Total impaired loans, unpaid principal balance	137,284	124,444
Total impaired loans, recorded investment	127,671	115,074
Commercial Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	23,953	24,037
Loans with no related allowance, recorded investment	23,373	23,121
Loans with related allowance, unpaid principal balance	14,082	5,216
Loans with related allowance, recorded investment	13,985	4,640
Allowance	1,461	1,827
Real Estate Construction Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	22,309	5,776
Loans with no related allowance, recorded investment	21,748	5,458
Commercial Real Estate Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	39,154	60,522
Loans with no related allowance, recorded investment	32,370	54,453
Loans with related allowance, unpaid principal balance	23,061	10,158
Loans with related allowance, recorded investment	22,820	10,017
Allowance	823	573
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	2,264	5,472
Loans with no related allowance, recorded investment	2,264	5,310
Loans with related allowance, unpaid principal balance	12,461	13,263
Loans with related allowance, recorded investment	11,111	12,075
Allowance	$ 322	$ 396