Note 7 - Loans (Detail) - Impaired Loans and Related Allowance For Credit Losses (USD $)	Sep. 30, 2012	Dec. 31, 2011
With allocated allowance
Allowance	$ 5,425,000	$ 7,554,000
Total impaired loans	340,400,000	432,972,000
Total impaired loans	265,096,000	321,973,000
Total impaired loans	5,425,000	7,554,000
Commercial Loans Member
With no allocated allowance
Loans with no related allowance unpaid principal balance	22,832,000	46,671,000
Loans with no related allowance recorded investment	17,561,000	38,194,000
Real Estate Construction Loans [Member]
With no allocated allowance
Loans with no related allowance unpaid principal balance	53,613,000	134,836,000
Loans with no related allowance recorded investment	40,877,000	78,767,000
Commercial Mortgage Loans [Member]
With no allocated allowance
Loans with no related allowance unpaid principal balance	204,549,000	187,580,000
Loans with no related allowance recorded investment	165,440,000	149,034,000
Residential Mortgage And Equity Lines Member
With no allocated allowance
Loans with no related allowance unpaid principal balance	4,318,000	8,555,000
Loans with no related allowance recorded investment	4,244,000	7,987,000
With No Allocated Allowance Member
With no allocated allowance
Loans with no related allowance unpaid principal balance	285,312,000	377,642,000
Loans with no related allowance recorded investment	228,122,000	273,982,000
Commercial Loans Member
With allocated allowance
Loans with related allowance unpaid principal balance	15,182,000	11,795,000
Loans with related allowance recorded investment	9,490,000	7,587,000
Allowance	1,791,000	3,336,000
Total impaired loans	1,791,000	3,336,000
Real Estate Construction Loans [Member]
With allocated allowance
Loans with related allowance unpaid principal balance	9,932,000
Loans with related allowance recorded investment	779,000
Allowance	279,000
Total impaired loans	279,000
Commercial Mortgage Loans [Member]
With allocated allowance
Loans with related allowance unpaid principal balance	13,902,000	29,722,000
Loans with related allowance recorded investment	12,969,000	28,023,000
Allowance	1,729,000	2,969,000
Total impaired loans	1,729,000	2,969,000
Residential Mortgage And Equity Lines Member
With allocated allowance
Loans with related allowance unpaid principal balance	16,072,000	13,813,000
Loans with related allowance recorded investment	13,736,000	12,381,000
Allowance	1,626,000	1,249,000
Total impaired loans	1,626,000	1,249,000
With Allocated Allowance Member
With allocated allowance
Loans with related allowance unpaid principal balance	55,088,000	55,330,000
Loans with related allowance recorded investment	36,974,000	47,991,000
Allowance	5,425,000	7,554,000
Total impaired loans	$ 5,425,000	$ 7,554,000