Note 5 - Loans (Detail) - Impaired Loans and Related Allowance For Credit Losses (USD $)	Dec. 31, 2012	Dec. 31, 2011
With allocated allowance
Allowance	$ 12,183,000	$ 7,554,000
Total impaired loans	323,786,000	432,973,000
Total impaired loans	248,597,000	321,973,000
Total impaired loans	12,183,000	7,554,000
Commercial Loans Member
With no allocated allowance
Loans with no related allowance unpaid principal balance	29,359,000	46,671,000
Loans with no related allowance recorded investment	18,963,000	38,194,000
Real Estate Construction Loans [Member]
With no allocated allowance
Loans with no related allowance unpaid principal balance	9,304,000	134,837,000
Loans with no related allowance recorded investment	7,277,000	78,767,000
Commercial Mortgage Loans [Member]
With no allocated allowance
Loans with no related allowance unpaid principal balance	189,871,000	187,580,000
Loans with no related allowance recorded investment	152,957,000	149,034,000
Residential Mortgage And Equity Lines Member
With no allocated allowance
Loans with no related allowance unpaid principal balance	4,303,000	8,555,000
Loans with no related allowance recorded investment	4,229,000	7,987,000
With No Allocated Allowance Member
With no allocated allowance
Loans with no related allowance unpaid principal balance	232,837,000	377,643,000
Loans with no related allowance recorded investment	183,426,000	273,982,000
Commercial Loans Member
With allocated allowance
Loans with related allowance unpaid principal balance	7,804,000	11,795,000
Loans with related allowance recorded investment	4,959,000	7,587,000
Allowance	1,467,000	3,336,000
Total impaired loans	1,467,000	3,336,000
Real Estate Construction Loans [Member]
With allocated allowance
Loans with related allowance unpaid principal balance	54,718,000
Loans with related allowance recorded investment	34,856,000
Allowance	8,158,000
Total impaired loans	8,158,000
Commercial Mortgage Loans [Member]
With allocated allowance
Loans with related allowance unpaid principal balance	14,163,000	29,722,000
Loans with related allowance recorded investment	12,928,000	28,023,000
Allowance	1,336,000	2,969,000
Total impaired loans	1,336,000	2,969,000
Residential Mortgage And Equity Lines Member
With allocated allowance
Loans with related allowance unpaid principal balance	14,264,000	13,813,000
Loans with related allowance recorded investment	12,428,000	12,381,000
Allowance	1,222,000	1,249,000
Total impaired loans	1,222,000	1,249,000
With Allocated Allowance Member
With allocated allowance
Loans with related allowance unpaid principal balance	90,949,000	55,330,000
Loans with related allowance recorded investment	65,171,000	47,991,000
Allowance	12,183,000	7,554,000
Total impaired loans	$ 12,183,000	$ 7,554,000