Note C - Marketable Equity Securities (Details) - Cost, Market Value and Unrealized Gain/(Loss) on Equity Securities (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Available-for-sale securities
Fair market value	$ 27,087us-gaap_AvailableForSaleSecurities	$ 24,592us-gaap_AvailableForSaleSecurities
Cost	16,667	14,272
Unrealized gain	10,420	10,320
Trading securities
Fair market value	290us-gaap_TradingSecurities	303us-gaap_TradingSecurities
Cost	157us-gaap_TradingSecuritiesCost	157us-gaap_TradingSecuritiesCost
Unrealized gain	133	146
Total
Fair market value	27,377us-gaap_MarketableSecuritiesCurrent	24,895us-gaap_MarketableSecuritiesCurrent
Cost	16,824	14,429
Unrealized gain	$ 10,553	$ 10,466

No authoritative reference available.

No definition available.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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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.

+ References

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- Definition

Amount of unrealized gain (loss) on investments in debt and equity securities classified as available-for-sale securities.

+ References

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- Definition

Amount of investments in debt and equity securities, including, but not limited to, held-to-maturity, trading and available-for-sale expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

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- Definition

The aggregate net change in the difference between the fair value and the carrying value, or in the comparative fair values, of marketable securities categorized as trading held at each balance sheet date, that was included in earnings for the period, which may have arisen from (a) securities classified as trading, (b) the unrealized holding gain (loss) on held-to-maturity securities transferred to the trading security category, and (c) the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) on available-for-sale securities transferred to trading securities during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 320

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- Definition

Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

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-Publisher FASB

-Name Accounting Standards Codification

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-Name Accounting Standards Codification

-Topic 942

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Cost of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

+ References

No definition available.

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- Definition

Amount of unrealized holding gain (loss) recognized in the income statement for investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

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