Note 3 - Investment Securities (Detail) - Investment Securities (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Cost	$ 408,522	$ 337,542
Gross Unrealized Gains	68	19
Gross Unrealized Losses	(85)	(88)
Market Value	408,505	337,473
Money Market Funds [Member]
Cost	51,210	3,689
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Market Value	51,210	3,689
Certificates of Deposit [Member]
Cost	0	5,862
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	0
Market Value	0	5,863
Commercial Paper [Member]
Cost	157,733	82,163
Gross Unrealized Gains	13	16
Gross Unrealized Losses	(56)	(42)
Market Value	157,690	82,137
Municipal Bonds [Member]
Cost	154,051	190,507
Gross Unrealized Gains	14	0
Gross Unrealized Losses	(16)	(33)
Market Value	154,049	190,474
US Government Corporations and Agencies Securities [Member]
Cost	23,015	22,011
Gross Unrealized Gains	1	2
Gross Unrealized Losses	(2)	0
Market Value	23,014	22,013
Corporate Debt Securities [Member]
Cost	22,513	33,310
Gross Unrealized Gains	40	0
Gross Unrealized Losses	(11)	(13)
Market Value	$ 22,542	$ 33,297

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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