Note 7 - Loans - Portfolio by Risk Rating (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Pass [Member] | Commercial Portfolio Segment [Member]
Loans	$ 2,027,815	$ 2,143,270
Pass [Member] | Real Estate Construction Portfolio Segment [Member]
Loans	489,473	413,765
Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans	5,391,701	5,018,199
Pass [Member] | Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans	2,488,495	2,091,434
Pass [Member] | Consumer Portfolio Segment [Member]
Loans	2,810	2,493
Pass [Member]
Loans	10,400,294	9,669,161
Loans held for sale		732
Special Mention [Member] | Commercial Portfolio Segment [Member]
Loans	133,858	110,338
Special Mention [Member] | Real Estate Construction Portfolio Segment [Member]
Loans	20,256	5,776
Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans	219,081	155,553
Special Mention [Member] | Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans	391	399
Special Mention [Member] | Consumer Portfolio Segment [Member]
Loans
Special Mention [Member]
Loans	373,586	272,066
Loans held for sale
Substandard [Member] | Commercial Portfolio Segment [Member]
Loans	86,806	61,297
Substandard [Member] | Real Estate Construction Portfolio Segment [Member]
Loans	5,507	21,502
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans	133,209	118,196
Substandard [Member] | Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans	10,538	9,502
Substandard [Member] | Consumer Portfolio Segment [Member]
Loans
Substandard [Member]
Loans	236,060	210,497
Loans held for sale		5,944
Doubtful [Member] | Commercial Portfolio Segment [Member]
Loans	517	1,958
Doubtful [Member] | Real Estate Construction Portfolio Segment [Member]
Loans		500
Doubtful [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans		9,270
Doubtful [Member] | Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans
Doubtful [Member] | Consumer Portfolio Segment [Member]
Loans
Doubtful [Member]
Loans	517	11,728
Loans held for sale	4,750
Commercial Portfolio Segment [Member]
Loans	2,248,996	2,316,863
Real Estate Construction Portfolio Segment [Member]
Loans	515,236	441,543
Commercial Real Estate Portfolio Segment [Member]
Loans	5,743,991	5,301,218
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans	2,499,424	2,101,335
Consumer Portfolio Segment [Member]
Loans	2,810	2,493
Loans	11,010,457	10,163,452
Loans held for sale	$ 4,750	$ 6,676