Note 1 - Accounting Policy (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Number of Operating Segments		1
Number of Reportable Segments		1
Federal Home Loan Bank Stock and Federal Reserve Bank Stock (in Dollars)		$ 9,500,000	$ 9,500,000
Deferred Finance Costs, Net (in Dollars)		574,000	691,000
Net Deferred Loan Costs Percent of Average Loans Outstanding		0.06%	0.06%
Interest Receivable (in Dollars)		6,100,000	6,600,000
Interest Receivable Percent Of Average Loans Outstanding		0.60%	0.60%
Loans Held-for-sale, Mortgages (in Dollars)		2,500,000	2,600,000
Mortgage Banking Revenues, Percent of Total Revenue		2.40%	1.28%	1.20%
Allowance for Loan and Lease Losses, Provision for Loss, Gross (in Dollars)		2,772,000	13,487,000	17,233,000
Impaired Loan Change (in Dollars)	28,000,000
Servicing Asset at Fair Value, Amount (in Dollars)		795,000	683,000
Mortgage Loans Serviced For Others (in Dollars)		172,000,000	146,000,000
Cash Reserve Deposit Required and Made (in Dollars)		17,000,000	15,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent		85.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in Shares)		23,368	34,769	33,071
Adjustments to Additional Paid in Capital, Share-based Compensation, Employee Stock Purchase Program, Requisite Service Period Recognition (in Dollars)		36,000	42,000	46,000
Furniture and Fixtures [Member] | Minimum [Member]
Property, Plant and Equipment, Estimated Useful Lives		two
Furniture and Fixtures [Member] | Maximum [Member]
Property, Plant and Equipment, Estimated Useful Lives		seven
Building and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment, Estimated Useful Lives		ten
Building and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment, Estimated Useful Lives		40
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in Shares)		24,049	24,049	24,049
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in Shares)			223,992	223,992
Impact of Method Change [Member]
Allowance for Loan and Lease Losses, Provision for Loss, Gross (in Dollars)	(2,900,000)
Impact Related to Impaired Loans [Member]
Allowance for Loan and Lease Losses, Provision for Loss, Gross (in Dollars)	$ 945,000
Minimum [Member]
Finite-Lived Intangible Asset, Useful Life		7 years
Maximum [Member]
Finite-Lived Intangible Asset, Useful Life		10 years