Note 3 - Securities Purchased Under Agreements to Resell (Detail) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Interest Income, Securities Purchased under Agreements to Resell	$ 18,000	$ 83,000	$ 14,000

Interest income derived from securities purchased under agreements to resell. The difference in the price at which the institution buys the securities and resells the securities represents interest for the use of the funds by the other party. Most repurchase and sale agreements involve obligations of the federal government or its agencies, but other financial instruments, such as commercial paper, banker's acceptances and negotiable certificates of deposits are sometimes used in such transactions.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.4)

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 4

-Article 9

Name:	us-gaap_InterestIncomeSecuritiesPurchasedUnderAgreementsToResell
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration