Note 7 - Loans - Accruing Troubled Debt Restructurings (Details) - Accruing Troubled Debt Restructuring [Member] - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Accruing TDRs	$ 80,419	$ 65,393	$ 90,172	$ 81,680
Payment Deferral [Member]
Accruing TDRs	64,277	39,054
Contractual Interest Rate Reduction [Member]
Accruing TDRs	6,535	6,750
Rate Reduction and Payment Deferral [Member]
Accruing TDRs	9,607	19,589
Commercial Portfolio Segment [Member]
Accruing TDRs	6,087	12,052
Commercial Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	5,752	7,971
Commercial Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs
Commercial Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	335	4,081
Real Estate Construction Loans [Member]
Accruing TDRs	27,683
Real Estate Construction Loans [Member] | Payment Deferral [Member]
Accruing TDRs	27,683
Real Estate Construction Loans [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs
Real Estate Construction Loans [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs
Commercial Real Estate Portfolio Segment [Member]
Accruing TDRs	38,155	44,392
Commercial Real Estate Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	25,806	25,979
Commercial Real Estate Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs	5,939	5,961
Commercial Real Estate Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	6,410	12,452
Residential Portfolio Segment [Member]
Accruing TDRs	8,494	8,949
Residential Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	5,036	5,104
Residential Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs	596	789
Residential Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	$ 2,862	$ 3,056