Note 7 - Loans (Details) - Allowance for Loan Losses by Portfolio Segment (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	$ 181,452		$ 181,452
Beginning Balance			183,322
Provision for possible credit losses			(675)	10,362
Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	66,736	65,738	66,736	65,738
Reserve for impaired loans	10,849	1,791	10,849	1,791
Reserve for non-impaired loans	55,887	63,947	55,887	63,947
Reserve for off-balance sheet credit commitments	953	801	953	801
Beginning Balance	64,379	66,595	66,101	65,658
Provision for possible credit losses	2,121	6,199	3,200	13,329
Charge-offs	(200)	(7,387)	(4,580)	(14,479)
Recoveries	436	331	2,015	1,230
Net charge-offs	236	(7,056)	(2,565)	(13,249)
Real Estate Construction Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	16,651	16,128	16,651	16,128
Reserve for impaired loans	5,691	279	5,691	279
Reserve for non-impaired loans	10,960	15,849	10,960	15,849
Reserve for off-balance sheet credit commitments	287	668	287	668
Beginning Balance	13,755	16,360	23,017	21,749
Provision for possible credit losses	1,660	(670)	(8,622)	(10,081)
Charge-offs	0	(39)	0	(1,165)
Recoveries	1,236	477	2,256	5,625
Net charge-offs	1,236	438	2,256	4,460
Commercial Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	86,088	92,011	86,088	92,011
Reserve for impaired loans	6,129	1,729	6,129	1,729
Reserve for non-impaired loans	79,959	90,282	79,959	90,282
Reserve for off-balance sheet credit commitments	799	104	799	104
Beginning Balance	89,678	99,009	82,473	108,021
Provision for possible credit losses	(5,710)	(6,350)	935	(12,937)
Charge-offs	(394)	(966)	(3,425)	(10,647)
Recoveries	2,514	318	6,105	7,574
Net charge-offs	2,120	(648)	2,680	(3,073)
Residential Mortgage And Equity Lines Member
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	11,942	10,528	11,942	10,528
Reserve for impaired loans	693	1,626	693	1,626
Reserve for non-impaired loans	11,249	8,902	11,249	8,902
Reserve for off-balance sheet credit commitments	34	34	34	34
Beginning Balance	11,892	10,254	11,703	10,795
Provision for possible credit losses	52	740	780	1,150
Charge-offs	(160)	(477)	(766)	(1,805)
Recoveries	158	11	225	388
Net charge-offs	(2)	(466)	(541)	(1,417)
Installment And Other Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	35	33	35	33
Reserve for impaired loans	0	0	0	0
Reserve for non-impaired loans	35	33	35	33
Reserve for off-balance sheet credit commitments	1	3	1	3
Beginning Balance	29	56	28	57
Provision for possible credit losses	6	(23)	(4)	(2)
Charge-offs	0	0	0	(25)
Recoveries	0	0	11	3
Net charge-offs	0	0	11	(22)
Total [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Ending Balance	181,452	184,438	181,452	184,438
Reserve for impaired loans	23,362	5,425	23,362	5,425
Reserve for non-impaired loans	158,090	179,013	158,090	179,013
Reserve for off-balance sheet credit commitments	2,074	1,610	2,074	1,610
Beginning Balance	179,733	192,274	183,322	206,280
Provision for possible credit losses	(1,871)	(104)	(3,711)	(8,541)
Charge-offs	(754)	(8,869)	(8,771)	(28,121)
Recoveries	4,344	1,137	10,612	14,820
Net charge-offs	$ 3,590	$ (7,732)	$ 1,841	$ (13,301)