Note 3 - Investment Securities Available for Sale (Detail) - Gross Unrealized Losses and Fair Value of the Investments (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Securities in Unrealized Loss Position Less Than 12 Months Fair Value	$ 3,510	$ 8,013
Securities in Unrealized Loss Position Less Than 12 Months Unrealized Losses	29	38
Securities in Unrealized Loss Position 12 Months or More Fair Value	2,104	3,952
Securities in Unrealized Loss Position 12 Months or More Unrealized Losses	22	48
Securities in Unrealized Loss Position Fair Value	5,614	11,965
Securities in Unrealized Loss Position Unrealized Losses	51	86
US States and Political Subdivisions Debt Securities [Member]
Securities in Unrealized Loss Position Less Than 12 Months Fair Value	2,512	4,033
Securities in Unrealized Loss Position Less Than 12 Months Unrealized Losses	27	18
Securities in Unrealized Loss Position 12 Months or More Fair Value	124
Securities in Unrealized Loss Position 12 Months or More Unrealized Losses	2
Securities in Unrealized Loss Position Fair Value	2,636	4,033
Securities in Unrealized Loss Position Unrealized Losses	29	18
Corporate Debt Securities [Member]
Securities in Unrealized Loss Position Less Than 12 Months Fair Value	998	3,980
Securities in Unrealized Loss Position Less Than 12 Months Unrealized Losses	2	20
Securities in Unrealized Loss Position 12 Months or More Fair Value	1,980	3,952
Securities in Unrealized Loss Position 12 Months or More Unrealized Losses	20	48
Securities in Unrealized Loss Position Fair Value	2,978	7,932
Securities in Unrealized Loss Position Unrealized Losses	$ 22	$ 68