Note 4 - Loans and Allowance for Loan Losses (Detail) - Loans Restructured as TDRs (USD $)	6 Months Ended
	Jun. 30, 2012
Consumer:
Number of Loans	30
Balance Prior to TDR	$ 1,152,000
Balance at March 31, 2012	951,000
Financial Impact on Date of Restructure	0
Restructured During Current Period [Member] | Credit Cards [Member]
Consumer:
Number of Loans	0
Restructured During Current Period [Member] | Student Loans [Member]
Consumer:
Number of Loans	0
Restructured During Current Period [Member] | Other Consumer [Member]
Consumer:
Number of Loans	1
Restructured During Current Period [Member] | Consumer Loans [Member]
Consumer:
Number of Loans	1
Restructured During Current Period [Member] | Single Family Residential Loans [Member]
Consumer:
Number of Loans	0
Restructured During Current Period [Member] | Other Commercial Real Estate Loans [Member]
Consumer:
Number of Loans	4
Restructured During Current Period [Member] | Real Estate Loans [Member]
Consumer:
Number of Loans	4
Restructured During Current Period [Member] | Other Commercial Loans [Member]
Consumer:
Number of Loans	1
Restructured During Current Period [Member] | Agricultural Loans [Member]
Consumer:
Number of Loans	0
Restructured During Current Period [Member] | Commercial Loans [Member]
Consumer:
Number of Loans	1
Restructured During Current Period [Member] | Other Loans [Member]
Consumer:
Number of Loans	0
Restructured During Current Period [Member]
Consumer:
Number of Loans	6
Change in Maturity Date [Member] | Credit Cards [Member]
Consumer:
Balance at March 31, 2012	0
Change in Maturity Date [Member] | Student Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Maturity Date [Member] | Other Consumer [Member]
Consumer:
Balance at March 31, 2012	0
Change in Maturity Date [Member] | Consumer Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Maturity Date [Member] | Construction Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Maturity Date [Member] | Single Family Residential Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Maturity Date [Member] | Other Commercial Real Estate Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Maturity Date [Member] | Real Estate Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Maturity Date [Member] | Other Commercial Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Maturity Date [Member] | Agricultural Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Maturity Date [Member] | Commercial Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Maturity Date [Member] | Other Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Maturity Date [Member]
Consumer:
Balance at March 31, 2012	0
Change in Rate [Member] | Credit Cards [Member]
Consumer:
Balance at March 31, 2012	0
Change in Rate [Member] | Student Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Rate [Member] | Other Consumer [Member]
Consumer:
Balance at March 31, 2012	33,000
Change in Rate [Member] | Consumer Loans [Member]
Consumer:
Balance at March 31, 2012	33,000
Change in Rate [Member] | Single Family Residential Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Rate [Member] | Other Commercial Real Estate Loans [Member]
Consumer:
Balance at March 31, 2012	879,000
Change in Rate [Member] | Real Estate Loans [Member]
Consumer:
Balance at March 31, 2012	879,000
Change in Rate [Member] | Other Commercial Loans [Member]
Consumer:
Balance at March 31, 2012	39,000
Change in Rate [Member] | Agricultural Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Rate [Member] | Commercial Loans [Member]
Consumer:
Balance at March 31, 2012	39,000
Change in Rate [Member] | Other Loans [Member]
Consumer:
Balance at March 31, 2012	0
Change in Rate [Member]
Consumer:
Balance at March 31, 2012	951,000
Credit Cards [Member]
Consumer:
Number of Loans	0
Balance Prior to TDR	0
Balance at March 31, 2012	0
Financial Impact on Date of Restructure	0
Student Loans [Member]
Consumer:
Number of Loans	0
Balance Prior to TDR	0
Balance at March 31, 2012	0
Financial Impact on Date of Restructure	0
Other Consumer [Member]
Consumer:
Number of Loans	3
Balance Prior to TDR	48,000
Balance at March 31, 2012	33,000
Financial Impact on Date of Restructure	0
Consumer Loans [Member]
Consumer:
Number of Loans	3
Balance Prior to TDR	48,000
Balance at March 31, 2012	33,000
Financial Impact on Date of Restructure	0
Construction Loans [Member]
Consumer:
Number of Loans	2
Financial Impact on Date of Restructure	0
Single Family Residential Loans [Member]
Consumer:
Number of Loans	4
Balance Prior to TDR	0
Balance at March 31, 2012	0
Financial Impact on Date of Restructure	0
Other Commercial Real Estate Loans [Member]
Consumer:
Number of Loans	17
Balance Prior to TDR	1,054,000
Balance at March 31, 2012	879,000
Financial Impact on Date of Restructure	0
Real Estate Loans [Member]
Consumer:
Number of Loans	23
Balance Prior to TDR	1,054,000
Balance at March 31, 2012	879,000
Financial Impact on Date of Restructure	0
Other Commercial Loans [Member]
Consumer:
Number of Loans	4
Balance Prior to TDR	50,000
Balance at March 31, 2012	39,000
Financial Impact on Date of Restructure	0
Agricultural Loans [Member]
Consumer:
Number of Loans	0
Balance Prior to TDR	0
Balance at March 31, 2012	0
Financial Impact on Date of Restructure	0
Commercial Loans [Member]
Consumer:
Number of Loans	4
Balance Prior to TDR	50,000
Balance at March 31, 2012	39,000
Financial Impact on Date of Restructure	0
Other Loans [Member]
Consumer:
Number of Loans	0
Balance Prior to TDR	0
Balance at March 31, 2012	0
Financial Impact on Date of Restructure	$ 0