Note 8 - Loans and the Allowance for Loan Losses (Detail) (USD $)	12 Months Ended													6 Months Ended										12 Months Ended
	Dec. 31, 2011	Jun. 30, 2012	Jun. 30, 2012 Loan Officers Maximum Secured Loans [Member]	Jun. 30, 2012 Loan Officers Maximum Unsecured Loans [Member]	Jun. 30, 2012 Managing Officers Maximum Secured Loans [Member]	Jun. 30, 2012 Managing Officers Maximum Unsecured Loans [Member]	Jun. 30, 2012 Senior Commercial Banking Officers Maximum Secured Loans [Member]	Jun. 30, 2012 Senior Commercial Banking Officer Maximum Unsecured Loans [Member]	Jun. 30, 2012 Chief Credit Officer Maximum Secured Loan [Member]	Jun. 30, 2012 Chief Credit Officer Maximum Unsecured Loan [Member]	Jun. 30, 2012 Executive Loan Committee One To Four Family Residential Mortgage Loans Maximum [Member]	Jun. 30, 2012 Executive Loan Committee Commercial Real Estate Multi-Family Real Estate and Land Loans Maximum [Member]	Jun. 30, 2012 Executive Loan Committee Maximum Unsecured Loan [Member]	Jun. 30, 2012 Troubled Debt Restructurings [Member]	Jun. 30, 2012 Residential Real Estate Loans [Member]	Jun. 30, 2012 Interest Only Payment Period [Member] Commercial Loans [Member]	Dec. 31, 2011 Interest Only Payment Period [Member] Commercial Loans [Member]	Jun. 30, 2012 Lengthening Amortization Period [Member] Commercial Loans [Member]	Dec. 31, 2011 Lengthening Amortization Period [Member] Commercial Real Estate Loans [Member]	Jun. 30, 2012 Charged Down or Charged Off [Member]	Dec. 31, 2011 Charged Down or Charged Off [Member]	Dec. 31, 2011 Federal Home Afforadable Modification Program [Member]	Dec. 31, 2011 Outside of HAMP [Member]	Dec. 31, 2011 Collateral Dependent [Member]	Jun. 30, 2011 Performing According to Modified Terms [Member] Commercial Loans [Member]	Jun. 30, 2011 Performing According to Modified Terms [Member] Residential Real Estate Loans [Member]	Jun. 30, 2011 Performing According to Modified Terms [Member] Commercial Real Estate Loans [Member]	Jun. 30, 2011 Performing According to Modified Terms [Member] Commerical Real Estate Development [Member]	Jun. 30, 2011 Performing According to Modified Terms [Member] Consumer Loans [Member]	Jun. 30, 2012 Commercial Loans [Member]	Dec. 31, 2011 Commercial Loans [Member]	Jun. 30, 2011 Commercial Loans [Member]	Jun. 30, 2012 Residential Real Estate Loans [Member]	Dec. 31, 2011 Residential Real Estate Loans [Member]	Jun. 30, 2011 Residential Real Estate Loans [Member]	Jun. 30, 2012 Commercial Real Estate Loans [Member]	Dec. 31, 2011 Commercial Real Estate Loans [Member]	Jun. 30, 2011 Commercial Real Estate Loans [Member]	Jun. 30, 2011 Commerical Real Estate Development [Member]	Jun. 30, 2012 Consumer Loans [Member]	Dec. 31, 2011 Consumer Loans [Member]	Jun. 30, 2011 Consumer Loans [Member]	Jun. 30, 2012 Commercial Real Estate Portfolio Segment [Member]	Dec. 31, 2011 Commercial Real Estate Portfolio Segment [Member]	Jun. 30, 2012 Commerical Real Estate Development [Member]	Dec. 31, 2011 Commerical Real Estate Development [Member]	Jun. 30, 2012 Agricultural [Member]	Dec. 31, 2011 Agricultural [Member]	Jun. 30, 2012 Agricultural Real Estate [Member]	Dec. 31, 2011 Agricultural Real Estate [Member]
Financing Receivable, Net	$ 621,021,000	$ 520,649,000	$ 100,000	$ 50,000	$ 250,000	$ 100,000	$ 750,000	$ 250,000	$ 1,500,000	$ 250,000	$ 2,500,000	$ 3,500,000	$ 1,000,000																	$ 50,914,000	$ 62,609,000	$ 129,771,000	$ 91,793,000	$ 97,172,000		$ 230,902,000	$ 235,103,000	$ 201,571,000		$ 41,196,000	$ 46,084,000		$ 230,902,000	$ 235,103,000	$ 30,124,000	$ 58,279,000	$ 22,392,000	$ 61,251,000	$ 53,328,000	$ 60,523,000
Financing Receivable Charge Off Rate	1.00%
Financing Receivable, Modifications, Number of Contracts	34	41													5	3	1	1	1	3	7	12	1	8										13
Financing Receivable, Modifications, Pre-Modification Recorded Investment															1,058,000	67,000	928,000	1,067,000	506,000			2,234,000	229,000											2,463,000
Financing Receivable, Allowance for Credit Losses, Write-downs	2,774,000													27,000
Financing Receivable, Modifications, Determination of Allowance for Credit Losses																								$467
Financing Receivable, Modifications, Recorded Investment	$ 19,378,000	$ 20,318,000																							$ 937	$ 3,186	$ 4,868	$ 5,293	$ 188			$ 937			$ 3,461			$ 15,071	$ 5,293			$ 188	$ 11,694,000	$ 11,588,000	$ 2,684,000	$ 2,711,000		$ 0		$ 0