Note 7 - Loans (Details) - Allowance for Loan Losses by Portfolio Segment (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for possible credit losses			$ 1,616	$ (894)
Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	64,782	61,056	65,103	66,101
Provision for possible credit losses	(6,111)	4,389	(1,228)	1,079
Charge-offs	(114)	(1,690)	(7,340)	(4,380)
Recoveries	4,682	624	6,704	1,579
Net charge-offs	4,568	(1,066)	(636)	(2,801)
Ending Balance	63,239	64,379	63,239	64,379
Reserve for impaired loans	2,717	1,568	2,717	1,568
Reserve for non-impaired loans	60,522	62,811	60,522	62,811
Reserve for off-balance sheet credit commitments	1,014	924	1,014	924
Real Estate Construction Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	10,626	20,697	11,999	23,017
Provision for possible credit losses	742	(7,883)	(656)	(10,282)
Charge-offs	(1,813)		(1,813)
Recoveries		941	25	1,020
Net charge-offs	(1,813)	941	(1,788)	1,020
Ending Balance	9,555	13,755	9,555	13,755
Reserve for impaired loans	143	4,995	143	4,995
Reserve for non-impaired loans	9,412	8,760	9,412	8,760
Reserve for off-balance sheet credit commitments	391	273	391	273
Commercial Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	81,326	84,816	84,753	82,473
Provision for possible credit losses	1,185	3,677	(3,041)	6,645
Charge-offs	(648)	(2,041)	(2,424)	(3,031)
Recoveries	1,532	3,226	4,107	3,591
Net charge-offs	884	1,185	1,683	560
Ending Balance	83,395	89,678	83,395	89,678
Reserve for impaired loans	6,230	5,342	6,230	5,342
Reserve for non-impaired loans	77,165	84,336	77,165	84,336
Reserve for off-balance sheet credit commitments	401	1,972	401	1,972
Residential Mortgage And Equity Lines Member
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	12,377	12,091	12,005	11,703
Provision for possible credit losses	493	(67)	865	728
Charge-offs		(196)		(606)
Recoveries		64		67
Net charge-offs		(132)		(539)
Ending Balance	12,870	11,892	12,870	11,892
Reserve for impaired loans	519	874	519	874
Reserve for non-impaired loans	12,351	11,018	12,351	11,018
Reserve for off-balance sheet credit commitments	36	33	36	33
Installment And Other Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	27	32	29	28
Provision for possible credit losses	(9)	(14)	(11)	(10)
Recoveries		11		11
Net charge-offs		11		11
Ending Balance	18	29	18	29
Reserve for impaired loans	0		0
Reserve for non-impaired loans	18	29	18	29
Reserve for off-balance sheet credit commitments	2	1	2	1
Total [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	169,138	178,692	173,889	183,322
Provision for possible credit losses	(3,700)	102	(4,071)	(1,840)
Charge-offs	(2,575)	(3,927)	(11,577)	(8,017)
Recoveries	6,214	4,866	10,836	6,268
Net charge-offs	3,639	939	(741)	(1,749)
Ending Balance	169,077	179,733	169,077	179,733
Reserve for impaired loans	9,609	12,779	9,609	12,779
Reserve for non-impaired loans	159,468	166,954	159,468	166,954
Reserve for off-balance sheet credit commitments	$ 1,844	$ 3,203	$ 1,844	$ 3,203