Note 7 - Loans (Detail) - Impaired Loans and Related Allowance For Credit Losses (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
With allocated allowance
Allowance	$ 17,357	$ 12,183
Total impaired loans	295,878	323,786
Total impaired loans	230,544	248,597
Total impaired loans	17,357	12,183
Commercial Loans Member
With no allocated allowance
Loans with no related allowance unpaid principal balance	14,437	29,359
Loans with no related allowance recorded investment	12,294	18,963
Real Estate Construction Loans [Member]
With no allocated allowance
Loans with no related allowance unpaid principal balance	9,304	9,304
Loans with no related allowance recorded investment	7,277	7,277
Commercial Mortgage Loans [Member]
With no allocated allowance
Loans with no related allowance unpaid principal balance	153,872	189,871
Loans with no related allowance recorded investment	120,563	152,957
Residential Mortgage And Equity Lines Member
With no allocated allowance
Loans with no related allowance unpaid principal balance	3,643	4,303
Loans with no related allowance recorded investment	3,633	4,229
With No Allocated Allowance Member
With no allocated allowance
Loans with no related allowance unpaid principal balance	181,256	232,837
Loans with no related allowance recorded investment	143,767	183,426
Commercial Loans Member
With allocated allowance
Loans with related allowance unpaid principal balance	11,854	7,804
Loans with related allowance recorded investment	7,180	4,959
Allowance	1,717	1,467
Total impaired loans	1,717	1,467
Real Estate Construction Loans [Member]
With allocated allowance
Loans with related allowance unpaid principal balance	54,657	54,718
Loans with related allowance recorded investment	34,795	34,856
Allowance	8,080	8,158
Total impaired loans	8,080	8,158
Commercial Mortgage Loans [Member]
With allocated allowance
Loans with related allowance unpaid principal balance	31,407	14,163
Loans with related allowance recorded investment	30,187	12,928
Allowance	6,242	1,336
Total impaired loans	6,242	1,336
Residential Mortgage And Equity Lines Member
With allocated allowance
Loans with related allowance unpaid principal balance	16,704	14,264
Loans with related allowance recorded investment	14,615	12,428
Allowance	1,318	1,222
Total impaired loans	1,318	1,222
With Allocated Allowance Member
With allocated allowance
Loans with related allowance unpaid principal balance	114,622	90,949
Loans with related allowance recorded investment	86,777	65,171
Allowance	17,357	12,183
Total impaired loans	$ 17,357	$ 12,183