Note 5 - Loans and Allowance for Loan Losses (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Loans and Leases Receivable, Net Reported Amount, Covered	$ 91,900,000		$ 101,700,000
Specific Review Loan Threshold	1,000,000
Threshold for Loans Evaluated for Impairment	150,000
Impaired Financing Receivable, Related Allowance	1,637,000		715,000
Impaired Financing Receivable, Interest Income, Accrual Method	86,000	37,000
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	2,000		77,000
Impaired Financing Receivable, Recorded Investment	17,252,000		17,742,000
Impaired Financing Receivable, Unpaid Principal Balance	33,476,000		25,362,000
Financing Receivable, Modifications, Number of Contracts	18		18
Financing Receivable, Modifications, Recorded Investment	9,200,000		10,200,000
Financing Receivable, Recorded Investment, Nonaccrual Status	9,725,000		10,374,000
Line of Credit Facility, Remaining Borrowing Capacity	3,000,000		1,800,000
Sold with Limited Recourse [Member]
Increase (Decrease) in Loans Held-for-sale	(30,100,000)	21,400,000
Pledged on FHLB Borrowings [Member]
Loans Pledged as Collateral	321,100,000		144,200,000
Pledged on the Federal Reserve Discount Window [Member]
Loans Pledged as Collateral	89,500,000		83,100,000
Performing Loans [Member] | Environmental Factors [Member]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	125,000
Purchased Credit Impaired Loans [Member] | Other Commercial [Member]
Impaired Financing Receivable, Related Allowance			225,000
Purchased Credit Impaired Loans [Member] | Acquisition, Construction, and Development Portfolio [Member]
Impaired Financing Receivable, Related Allowance			542,000
Purchased Credit Impaired Loans [Member] | Residential Mortgage Loans [Member]
Impaired Financing Receivable, Related Allowance			200,000
Purchased Credit Impaired Loans [Member]
Impaired Financing Receivable, Recorded Investment	216,000,000		234,300,000
Accruing TDRs [Member]
Impaired Financing Receivable, Interest Income, Accrual Method	86,000	37,000
Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status	1,800,000
Purchased Credit Impaired Loans [Member]
Loans and Leases Receivable, Net Reported Amount, Covered	87,700,000		96,900,000
Impaired Financing Receivable, Related Allowance	436,000
Impaired Financing Receivable, Recorded Investment	257,500,000
Impaired Financing Receivable, Unpaid Principal Balance			278,200,000
Percentage of Total Assets	10.90%		11.50%
All Other Loans [Member]
Loans and Leases Receivable, Net Reported Amount, Covered	4,200,000		4,800,000
Loans Sold to Other Financial Institutions [Member]
Loans Receivable, Net	11,600,000		10,800,000
Other Commercial [Member]
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivable, Interest Income, Accrual Method	0
Impaired Financing Receivable, Recorded Investment	164,000		168,000
Impaired Financing Receivable, Unpaid Principal Balance	172,000		172,000
Financing Receivable, Recorded Investment, Nonaccrual Status	164,000		168,000
Acquisition, Construction, and Development Portfolio [Member]
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivable, Interest Income, Accrual Method	18,000	21,000
Impaired Financing Receivable, Recorded Investment	3,547,000		4,855,000
Impaired Financing Receivable, Unpaid Principal Balance	10,445,000		9,306,000
Financing Receivable, Recorded Investment, Nonaccrual Status	2,578,000		3,872,000
Residential Mortgage Loans [Member]
Impaired Financing Receivable, Related Allowance	247,000		249,000
Impaired Financing Receivable, Interest Income, Accrual Method	27,000	9,000
Impaired Financing Receivable, Recorded Investment	3,559,000		3,463,000
Impaired Financing Receivable, Unpaid Principal Balance	4,306,000		3,613,000
Financing Receivable, Recorded Investment, Nonaccrual Status	1,051,000		1,096,000
Troubled Debt Restructurings [Member]
Impaired Financing Receivable, Related Allowance	242,000		54,000
Financing Receivable, Recorded Investment, Nonaccrual Status			$ 2,800,000