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, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	$ 179,733		$ 179,733
Beginning Balance			183,322
Provision for possible credit losses			(894)	7,487
Commercial Loans Member
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	64,379	66,595	64,379	66,595
Beginning Balance	61,056	60,404	66,101	65,658
Recoveries	624	153	1,579	899
Net charge-offs	(1,066)	(1,980)	(2,801)	(6,193)
Provision for possible credit losses	4,389	8,171	1,079	7,130
Charge-offs	(1,690)	(2,133)	(4,380)	(7,092)
Reserve for impaired loans	1,568	3,687	1,568	3,687
Reserve for non-impaired loans	62,811	62,908	62,811	62,908
Reserve for off-balance sheet credit commitments	924	747	924	747
Real Estate Construction Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	13,755	16,360	13,755	16,360
Beginning Balance	20,697	17,992	23,017	21,749
Recoveries	941	1,591	1,020	5,148
Net charge-offs	941	1,340	1,020	4,022
Provision for possible credit losses	(7,883)	(2,972)	(10,282)	(9,411)
Charge-offs	0	(251)	0	(1,126)
Reserve for impaired loans	4,995	0	4,995	0
Reserve for non-impaired loans	8,760	16,360	8,760	16,360
Reserve for off-balance sheet credit commitments	273	617	273	617
Commercial Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	89,678	99,009	89,678	99,009
Beginning Balance	84,816	106,175	82,473	108,021
Recoveries	3,226	5,198	3,591	7,256
Net charge-offs	1,185	3,740	560	(2,425)
Provision for possible credit losses	3,677	(10,906)	6,645	(6,587)
Charge-offs	(2,041)	(1,458)	(3,031)	(9,681)
Reserve for impaired loans	5,342	1,896	5,342	1,896
Reserve for non-impaired loans	84,336	97,113	84,336	97,113
Reserve for off-balance sheet credit commitments	1,972	104	1,972	104
Residential Mortgage And Equity Lines Member
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	11,892	10,254	11,892	10,254
Beginning Balance	12,091	10,122	11,703	10,795
Recoveries	64	11	67	377
Net charge-offs	(132)	(539)	(539)	(951)
Provision for possible credit losses	(67)	671	728	410
Charge-offs	(196)	(550)	(606)	(1,328)
Reserve for impaired loans	874	1,659	874	1,659
Reserve for non-impaired loans	11,018	8,595	11,018	8,595
Reserve for off-balance sheet credit commitments	33	35	33	35
Installment And Other Loans Member
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	29	56	29	56
Beginning Balance	32	50	28	57
Recoveries	11		11	3
Net charge-offs	11		11	(22)
Provision for possible credit losses	(14)	6	(10)	21
Charge-offs				(25)
Reserve for impaired loans		0		0
Reserve for non-impaired loans	29	56	29	56
Reserve for off-balance sheet credit commitments	1	2	1	2
Total [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	179,733	192,274	179,733	192,274
Beginning Balance	178,692	194,743	183,322	206,280
Recoveries	4,866	6,953	6,268	13,683
Net charge-offs	939	2,561	(1,749)	(5,569)
Provision for possible credit losses	102	(5,030)	(1,840)	(8,437)
Charge-offs	(3,927)	(4,392)	(8,017)	(19,252)
Reserve for impaired loans	12,779	7,242	12,779	7,242
Reserve for non-impaired loans	166,954	185,032	166,954	185,032
Reserve for off-balance sheet credit commitments	$ 3,203	$ 1,505	$ 3,203	$ 1,505