Note 3 - Loans (Detail) - Impaired Loans (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Impaired loans with no allocated allowance for loan losses - related allowance		$ 3,875
Impaired loans with allocated allowance for loan losses - related allowance		3,875
Total
Impaired loans - recorded investment		38,008
Impaired loans - unpaid principal balance		50,756
Impaired loans - related allowance		3,875
Commercial and Industrial [Member] | Period End Loans No Allocated Allowance For Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - recorded investment	1,898	4,358
Impaired loans with no allocated allowance for loan losses - unpaid principal balance	1,897	5,846
Impaired loans with no allocated allowance for loan losses - related allowance	0	0
Impaired loans with allocated allowance for loan losses - related allowance	0	0
Total
Impaired loans - related allowance	0	0
Commercial and Industrial [Member] | Period End Loans Allocated Allowance Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - related allowance	321	253
Impaired loans with allocated allowance for loan losses - recorded investment	458	720
Impaired loans with allocated allowance for loan losses - unpaid principal balance	778	998
Impaired loans with allocated allowance for loan losses - related allowance	321	253
Total
Impaired loans - related allowance	321	253
Commercial and Industrial [Member]
Impaired loans with no allocated allowance for loan losses - related allowance	321	253
Impaired loans with allocated allowance for loan losses - related allowance	321	253
Total
Impaired loans - recorded investment	2,356	5,078
Impaired loans - unpaid principal balance	2,675	6,844
Impaired loans - related allowance	321	253
Commercial Real Estate Other Receivable [Member] | Period End Loans No Allocated Allowance For Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - recorded investment	10,205	11,940
Impaired loans with no allocated allowance for loan losses - unpaid principal balance	10,201	16,987
Impaired loans with no allocated allowance for loan losses - related allowance	0	0
Impaired loans with allocated allowance for loan losses - related allowance	0	0
Total
Impaired loans - related allowance	0	0
Commercial Real Estate Other Receivable [Member] | Period End Loans Allocated Allowance Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - related allowance	3,365	3,622
Impaired loans with allocated allowance for loan losses - recorded investment	9,060	10,423
Impaired loans with allocated allowance for loan losses - unpaid principal balance	12,423	15,225
Impaired loans with allocated allowance for loan losses - related allowance	3,365	3,622
Total
Impaired loans - related allowance	3,365	3,622
Commercial Real Estate Other Receivable [Member]
Impaired loans with no allocated allowance for loan losses - related allowance	3,365	3,622
Impaired loans with allocated allowance for loan losses - related allowance	3,365	3,622
Total
Impaired loans - recorded investment	19,265	22,363
Impaired loans - unpaid principal balance	22,624	32,212
Impaired loans - related allowance	3,365	3,622
First Lien Residential Mortgage Loans [Member] | Period End Loans No Allocated Allowance For Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - recorded investment	9,392	9,799
Impaired loans with no allocated allowance for loan losses - unpaid principal balance	9,392	11,120
Impaired loans with no allocated allowance for loan losses - related allowance	0	0
Impaired loans with allocated allowance for loan losses - related allowance	0	0
Total
Impaired loans - related allowance	0	0
First Lien Residential Mortgage Loans [Member] | Period End Loans Allocated Allowance Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - related allowance	0	0
Impaired loans with allocated allowance for loan losses - recorded investment	0	0
Impaired loans with allocated allowance for loan losses - unpaid principal balance	0	0
Impaired loans with allocated allowance for loan losses - related allowance	0	0
Total
Impaired loans - related allowance	0	0
First Lien Residential Mortgage Loans [Member]
Impaired loans with no allocated allowance for loan losses - related allowance	0	0
Impaired loans with allocated allowance for loan losses - related allowance	0	0
Total
Impaired loans - recorded investment	9,392	9,799
Impaired loans - unpaid principal balance	9,392	11,120
Impaired loans - related allowance	0	0
Junior Lein Residential Mortgage Loans [Member] | Period End Loans No Allocated Allowance For Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - recorded investment	610	558
Impaired loans with no allocated allowance for loan losses - unpaid principal balance	610	331
Impaired loans with no allocated allowance for loan losses - related allowance	0	0
Impaired loans with allocated allowance for loan losses - related allowance	0	0
Total
Impaired loans - related allowance	0	0
Junior Lein Residential Mortgage Loans [Member] | Period End Loans Allocated Allowance Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - related allowance	0	0
Impaired loans with allocated allowance for loan losses - recorded investment	0	0
Impaired loans with allocated allowance for loan losses - unpaid principal balance	0	0
Impaired loans with allocated allowance for loan losses - related allowance	0	0
Total
Impaired loans - related allowance	0	0
Junior Lein Residential Mortgage Loans [Member]
Impaired loans with no allocated allowance for loan losses - related allowance	0	0
Impaired loans with allocated allowance for loan losses - related allowance	0	0
Total
Impaired loans - recorded investment	610	558
Impaired loans - unpaid principal balance	610	331
Impaired loans - related allowance	0	0
Consumer Loans [Member] | Period End Loans No Allocated Allowance For Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - recorded investment	445	210
Impaired loans with no allocated allowance for loan losses - unpaid principal balance	445	249
Impaired loans with no allocated allowance for loan losses - related allowance	0	0
Impaired loans with allocated allowance for loan losses - related allowance	0	0
Total
Impaired loans - related allowance	0	0
Consumer Loans [Member] | Period End Loans Allocated Allowance Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - related allowance	0	0
Impaired loans with allocated allowance for loan losses - recorded investment	0	0
Impaired loans with allocated allowance for loan losses - unpaid principal balance	0	0
Impaired loans with allocated allowance for loan losses - related allowance	0	0
Total
Impaired loans - related allowance	0	0
Consumer Loans [Member]
Impaired loans with no allocated allowance for loan losses - related allowance	0	0
Impaired loans with allocated allowance for loan losses - related allowance	0	0
Total
Impaired loans - recorded investment	445	210
Impaired loans - unpaid principal balance	445	249
Impaired loans - related allowance	0	0
No Allocated Allowance [Member] | Period End Loans No Allocated Allowance For Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - recorded investment	22,550
Impaired loans with no allocated allowance for loan losses - unpaid principal balance	22,545
Impaired loans with no allocated allowance for loan losses - related allowance	0
Impaired loans with allocated allowance for loan losses - related allowance	0
Total
Impaired loans - related allowance	0
No Allocated Allowance [Member] | Period End Loans Allocated Allowance Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - related allowance	3,686
Impaired loans with allocated allowance for loan losses - recorded investment	9,518
Impaired loans with allocated allowance for loan losses - unpaid principal balance	13,201
Impaired loans with allocated allowance for loan losses - related allowance	3,686
Total
Impaired loans - related allowance	3,686
No Allocated Allowance [Member]
Impaired loans with no allocated allowance for loan losses - related allowance	3,686
Impaired loans with allocated allowance for loan losses - related allowance	3,686
Total
Impaired loans - recorded investment	32,068
Impaired loans - unpaid principal balance	35,746
Impaired loans - related allowance	3,686
Period End Loans No Allocated Allowance For Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - recorded investment		26,865
Impaired loans with no allocated allowance for loan losses - unpaid principal balance		34,533
Impaired loans with no allocated allowance for loan losses - related allowance		0
Impaired loans with allocated allowance for loan losses - related allowance		0
Total
Impaired loans - related allowance		0
Period End Loans Allocated Allowance Loan Losses [Member]
Impaired loans with no allocated allowance for loan losses - related allowance		3,875
Impaired loans with allocated allowance for loan losses - recorded investment		11,143
Impaired loans with allocated allowance for loan losses - unpaid principal balance		16,223
Impaired loans with allocated allowance for loan losses - related allowance		3,875
Total
Impaired loans - related allowance		$ 3,875