Note 2 - Fair Value of Financial Instruments (Detail) - Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Commercial Real Estate Construction Financing Receivable [Member] | Other Real Estate Owned [Member] | Fair Value, Inputs, Level 3 [Member]
Commercial real estate:
Assets measured on a nonrecurring basis		$ 1,562
Commercial Real Estate Construction Financing Receivable [Member]
Commercial real estate:
Assets measured on a nonrecurring basis		1,562
Commercial and Industrial [Member] | Other Real Estate Owned [Member] | Fair Value, Inputs, Level 3 [Member]
Commercial real estate:
Assets measured on a nonrecurring basis		1,055
Commercial and Industrial [Member]
Commercial real estate:
Assets measured on a nonrecurring basis		1,055
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets measured on a recurring basis	9,014	1,012
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Inputs, Level 2 [Member]
Assets measured on a recurring basis	$ 90,501	$ 93,953