Note 7 - Loans (Details) - Allowance for Loan Losses by Portfolio Segment (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance	$ 47,501	$ 65,103
Provision/(reversal) for possible loan losses	793	4,888
Charge-offs	(864)	(7,226)
Recoveries	2,275	2,017
Net charge-offs	1,411	(5,209)
Balance	49,705	64,782
Reserve to impaired loans	3,911	4,663
Reserve to non-impaired loans	45,794	60,119
Reserve for off-balance sheet credit commitments	903	929
Real Estate Construction Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance	27,652	11,999
Provision/(reversal) for possible loan losses	(4,427)	(1,398)
Recoveries	45	25
Net charge-offs	45	25
Balance	23,270	10,626
Reserve to impaired loans		3,129
Reserve to non-impaired loans	23,270	7,497
Reserve for off-balance sheet credit commitments	527	326
Commercial Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance	74,673	84,753
Provision/(reversal) for possible loan losses	(1,697)	(4,306)
Charge-offs	(3,452)	(1,698)
Recoveries	1,794	2,577
Net charge-offs	(1,658)	879
Balance	71,318	81,326
Reserve to impaired loans	6,635	6,165
Reserve to non-impaired loans	64,683	75,161
Reserve for off-balance sheet credit commitments	181	445
Residential Mortgage and Equity Lines [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance	11,578	12,005
Provision/(reversal) for possible loan losses	328	447
Charge-offs	(148)	(78)
Recoveries	19	3
Net charge-offs	(129)	(75)
Balance	11,777	12,377
Reserve to impaired loans	498	538
Reserve to non-impaired loans	11,279	11,839
Reserve for off-balance sheet credit commitments	40	33
Installment And Other Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance	16	29
Provision/(reversal) for possible loan losses	3	(2)
Balance	19	27
Reserve to impaired loans		0
Reserve to non-impaired loans	19	27
Reserve for off-balance sheet credit commitments	1	1
Total [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance	161,420	173,889
Provision/(reversal) for possible loan losses	(5,000)	(371)
Charge-offs	(4,464)	(9,002)
Recoveries	4,133	4,622
Net charge-offs	(331)	(4,380)
Balance	156,089	169,138
Reserve to impaired loans	11,044	14,495
Reserve to non-impaired loans	145,045	154,643
Reserve for off-balance sheet credit commitments	$ 1,652	$ 1,734