Note 7 - Investments in Affordable Housing (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Affordable Housing Investments	$ 85,037,000	$ 78,358,000
Number of Limited Partnerships in Housing Investments	6
Increase In Total Assets And Liabilities From Consolidating Affordable Housing Equity Interest	22,900,000	22,800,000
Other Borrowings From Consolidating Affordable Housing Equity Interest	18,700,000	18,900,000
Other Liabilities From Affordable Housing Unfunded Commitments	10,600,000	1,500,000
Minimum Compliance Period, Tax Credits, Investments In Affordable Housing	15 years
Income Tax Reconciliation, Tax Credits, Investment	9,200,000	9,500,000	10,500,000
PreTaxLossesInvestmentsInAffordableHousing	6,300,000	8,200,000	7,600,000
Federal Tax [Member] | Affordable Housing Limited Partnerships [Member]
Tax Credit Carryforward, Amount	45,300,000
State and Local Jurisdiction [Member] | Affordable Housing Limited Partnerships [Member]
Tax Credit Carryforward, Amount	$ 1,700,000