Note 5 - Loans - Non-accrual Troubled Debt Restructurings (Details) - Non-accruing Troubled Debt Restructuring [Member] - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accruing TDRs	$ 29,722	$ 39,923	$ 41,618	$ 38,769
Payment Deferral [Member]
Accruing TDRs	17,431	12,946
Contractual Interest Rate Reduction [Member]
Accruing TDRs	1,795
Rate Reduction and Payment Deferral [Member]
Accruing TDRs	10,496	26,977
Commercial Portfolio Segment [Member]
Accruing TDRs	14,565	1,123
Commercial Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	14,565	1,033
Commercial Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs
Commercial Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs		90
Real Estate Construction Portfolio Segment [Member]
Accruing TDRs		15,806
Real Estate Construction Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs		9,981
Real Estate Construction Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs		5,825
Commercial Real Estate Portfolio Segment [Member]
Accruing TDRs	14,633	21,906
Commercial Real Estate Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	2,510	1,544
Commercial Real Estate Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs	1,795
Commercial Real Estate Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	10,328	20,362
Residential Portfolio Segment [Member]
Accruing TDRs	524	1,088
Residential Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	356	388
Residential Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs
Residential Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	$ 168	$ 700