Note 3 - Investment Securities Available for Sale (Detail) - Amortized Cost And Estimated Fair Value Of Securities Available For Sale (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Amortized Cost	$ 310,917	$ 290,712
Gross Unrealized Gains	8,430	9,521
Gross Unrealized Losses	916	413
Estimated Fair Value	318,431	299,820
US Government Agencies Debt Securities [Member]
Amortized Cost	38,902	47,606
Gross Unrealized Gains	1,229	1,477
Gross Unrealized Losses	7	1
Estimated Fair Value	40,124	49,082
Residential Mortgage Backed Securities [Member]
Amortized Cost	189,601	170,649
Gross Unrealized Gains	2,514	2,730
Gross Unrealized Losses	537	296
Estimated Fair Value	191,578	173,083
Municipal Bond [Member]
Amortized Cost	82,007	72,050
Gross Unrealized Gains	4,687	5,314
Gross Unrealized Losses	314	51
Estimated Fair Value	86,380	77,313
Equity Investment Other [Member]
Amortized Cost	407	407
Gross Unrealized Losses	58	65
Estimated Fair Value	$ 349	$ 342

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

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