Note 8 - Loans and the Allowance for Loan Losses (Detail) - Loans Modified as Troubled Debt Restructurings (USD $)	Jun. 30, 2012	Dec. 31, 2011
Number of Modifications	41	34
Recorded Investment (in Dollars)	$ 20,318,000	$ 19,378,000
Modified in Reporting Period [Member] | Commercial Portfolio Segment [Member]
Number of Modifications	3	1
Recorded Investment (in Dollars)	19,000	928,000
Modified in Reporting Period [Member] | Agricultural [Member]
Number of Modifications		0
Recorded Investment (in Dollars)		0
Modified in Reporting Period [Member] | Agricultural Real Estate [Member]
Number of Modifications		0
Recorded Investment (in Dollars)		0
Modified in Reporting Period [Member] | Commercial Real Estate Portfolio Segment [Member]
Number of Modifications	1	1
Recorded Investment (in Dollars)	1,063,000	506,000
Modified in Reporting Period [Member] | Commerical Real Estate Development [Member]
Number of Modifications		0
Recorded Investment (in Dollars)		0
Modified in Reporting Period [Member] | Residential Real Estate Loans [Member]
Number of Modifications	5	13
Recorded Investment (in Dollars)	1,058,000	2,463,000
Modified in Reporting Period [Member] | Consumer Portfolio Segment [Member]
Number of Modifications	1	0
Recorded Investment (in Dollars)	9,000	0
Modified in Reporting Period [Member]
Number of Modifications	10	15
Recorded Investment (in Dollars)	2,149,000	3,897,000
Commercial Portfolio Segment [Member]
Recorded Investment (in Dollars)	1,185,000	928,000
Agricultural [Member]
Recorded Investment (in Dollars)		0
Agricultural Real Estate [Member]
Recorded Investment (in Dollars)		0
Commercial Real Estate Portfolio Segment [Member]
Recorded Investment (in Dollars)	11,694,000	11,588,000
Commerical Real Estate Development [Member]
Recorded Investment (in Dollars)	2,684,000	2,711,000
Residential Real Estate Loans [Member]
Recorded Investment (in Dollars)	4,707,000	3,963,000
Consumer Portfolio Segment [Member]
Recorded Investment (in Dollars)	$ 48,000	$ 188,000