Note 5 - Loans and Allowance for Loan Losses (Detail) - Troubled Debt Restructurings Outcomes (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Troubled Debt Restructurings - Number of loans	18	18
Troubled Debt Restructurings - Recorded Investment (in Dollars)	$ 9,200	$ 10,200
Paying as Restructured [Member] | Below Market Interest Rate [Member]
Troubled Debt Restructurings - Number of loans	2	1
Troubled Debt Restructurings - Recorded Investment (in Dollars)	3,653	394
Paying as Restructured [Member] | Total [Member]
Troubled Debt Restructurings - Number of loans	2	4
Troubled Debt Restructurings - Recorded Investment (in Dollars)	3,653	851
Paying as Restructured [Member] | Extended Payment Terms [Member]
Troubled Debt Restructurings - Number of loans		2
Troubled Debt Restructurings - Recorded Investment (in Dollars)		434
Paying as Restructured [Member] | Forgiveness of Principal [Member]
Troubled Debt Restructurings - Number of loans		1
Troubled Debt Restructurings - Recorded Investment (in Dollars)		23
Nonaccrual [Member] | Below Market Interest Rate [Member]
Troubled Debt Restructurings - Number of loans	0	1
Troubled Debt Restructurings - Recorded Investment (in Dollars)	0	273
Nonaccrual [Member] | Total [Member]
Troubled Debt Restructurings - Number of loans	0	4
Troubled Debt Restructurings - Recorded Investment (in Dollars)	0	776
Nonaccrual [Member] | Extended Payment Terms [Member]
Troubled Debt Restructurings - Number of loans		2
Troubled Debt Restructurings - Recorded Investment (in Dollars)		503
Nonaccrual [Member] | Forgiveness of Principal [Member]
Troubled Debt Restructurings - Number of loans		1
Troubled Debt Restructurings - Recorded Investment (in Dollars)		0
Foreclosure/Default [Member] | Below Market Interest Rate [Member]
Troubled Debt Restructurings - Number of loans	0	0
Troubled Debt Restructurings - Recorded Investment (in Dollars)	0	0
Foreclosure/Default [Member] | Total [Member]
Troubled Debt Restructurings - Number of loans	0	4
Troubled Debt Restructurings - Recorded Investment (in Dollars)	0	0
Foreclosure/Default [Member] | Extended Payment Terms [Member]
Troubled Debt Restructurings - Number of loans		0
Troubled Debt Restructurings - Recorded Investment (in Dollars)		0
Foreclosure/Default [Member] | Forgiveness of Principal [Member]
Troubled Debt Restructurings - Number of loans		4
Troubled Debt Restructurings - Recorded Investment (in Dollars)		$ 0