Note 7 - Loans (Details) - Allowance for Loan Losses by Portfolio Segment - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning	$ 138,963	$ 161,420
Provision/(reversal) for possible loan losses	(10,500)	(5,000)
Charge-offs	(2,329)	(4,464)
Recoveries	8,418	4,133
Net charge-offs	6,089	(331)
Balance, ending	134,552	156,089
Reserve to impaired loans	7,190	11,044
Reserve to non-impaired loans	127,362	145,045
Reserve for off-balance sheet credit commitments	2,694	1,652
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning	56,199	47,501
Provision/(reversal) for possible loan losses	1,265	793
Charge-offs	(2,070)	(864)
Recoveries	987	2,275
Net charge-offs	(1,083)	1,411
Balance, ending	56,381	49,705
Reserve to impaired loans	225	3,911
Reserve to non-impaired loans	56,156	45,794
Reserve for off-balance sheet credit commitments	2,641	903
Real Estate Construction Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning	22,170	27,652
Provision/(reversal) for possible loan losses	(16,702)	(4,427)
Recoveries	7,276	45
Net charge-offs	7,276	45
Balance, ending	12,744	23,270
Reserve to non-impaired loans	12,744	23,270
Reserve for off-balance sheet credit commitments		527
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning	49,440	74,673
Provision/(reversal) for possible loan losses	978	(1,697)
Charge-offs	(110)	(3,452)
Recoveries	143	1,794
Net charge-offs	33	(1,658)
Balance, ending	50,451	71,318
Reserve to impaired loans	6,593	6,635
Reserve to non-impaired loans	43,858	64,683
Reserve for off-balance sheet credit commitments	53	181
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning	11,145	11,578
Provision/(reversal) for possible loan losses	3,961	328
Charge-offs	(149)	(148)
Recoveries	12	19
Net charge-offs	(137)	(129)
Balance, ending	14,969	11,777
Reserve to impaired loans	372	498
Reserve to non-impaired loans	14,597	11,279
Reserve for off-balance sheet credit commitments		40
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning	9	16
Provision/(reversal) for possible loan losses	(2)	3
Balance, ending	7	19
Reserve to impaired loans	0
Reserve to non-impaired loans	$ 7	19
Reserve for off-balance sheet credit commitments		$ 1