Note 4 - Loans and Allowance for Credit Losses (Detail) (USD $)	3 Months Ended	9 Months Ended
	Dec. 31, 2011	Sep. 30, 2012	Sep. 30, 2011
Loans and Leases Receivable, Deferred Income	$ 5,200,000	$ 8,100,000
Servicing Asset at Fair Value, Amount	27,300,000	28,300,000
Interest Rate Adjustment Frequency		5 years
Stress Test Assumption Increase Interest Rates (in Basis Points)		2.00%
	100.00%	100.00%	100.00%
Impaired Financing Receivable, Recorded Investment	46,667,000	41,206,000	44,045,000
Impaired Financing Receivable, Unpaid Principal Balance	46,667,000	41,206,000	44,045,000
Troubled Debt Restructuring, Debtor, Other	$13.9	$1.2	$3.1
Interest Income (Expense), Gross		97,000
Loans Receivable, Net		2,800,000
Nonperforming Financing Receivable [Member]
Impaired Financing Receivable, Recorded Investment		2,100,000
Impaired Financing Receivable, Unpaid Principal Balance		11,700,000
Commercial Real Estate and Real Estate Construction Loans [Member]
Percent Of Loan Portfolio		71.00%
Commercial Real Estate Owner Occupied [Member]
Percent Of Loan Portfolio		14.00%
Impaired Financing Receivable, Recorded Investment	282,000	2,374,000	1,080,000
Impaired Financing Receivable, Unpaid Principal Balance	282,000	2,374,000	1,080,000
Excluding Owner Occupied Commercial Real Estate And Commercial Construction Loans [Member]
Percent Of Loan Portfolio		57.00%
Commercial Loan [Member]
Percent Of Loan Portfolio		23.00%
Length Of Loan		10 years
Impaired Financing Receivable, Recorded Investment	10,695,000	7,282,000	10,742,000
Impaired Financing Receivable, Unpaid Principal Balance	10,695,000	7,282,000	10,742,000
SBA Loans [Member]
Percent Of Loan Portfolio		2.00%
Home Equity Line of Credit [Member]
Percent Of Loan Portfolio		4.00%
Impaired Financing Receivable, Recorded Investment	624,000	670,000	664,000
Impaired Financing Receivable, Unpaid Principal Balance	624,000	670,000	664,000
Residential Mortgage Loan Long-Term [Member]
Percent Of Loan Portfolio		2.00%
Length Of Loan		10 years
Commercial Land Acquisition Loans [Member]
Length Of Loan		24 months
ADC Loans [Member]
Financing Receivable, Net		452,600,000
		34.00%
TDR [Member]
Loans and Leases Receivable, Deferred Income		8,800,000
Maximum [Member]
Loan To Value Ratio		80.00%
Minimum Debt Service Coverage (in Basis Points)		0.0115%
Length Of Loan		7 years
Amortization Term		25 years
Minimum [Member]
Minimum Debt Service Coverage (in Basis Points)		0.01%
Length Of Loan		5 years
Expected if Nonaccrual Loans had been Current [Member]
Interest Income (Expense), Gross		1,800
Construction Loans [Member]
Length Of Loan		36 months
Impaired Financing Receivable, Recorded Investment	22,812,000	24,371,000	23,752,000
Impaired Financing Receivable, Unpaid Principal Balance	$ 22,812,000	$ 24,371,000	$ 23,752,000