Note K - Accounting for Stock-based Compensation (Details) - Restricted Stock Unit Activity (Restricted Stock Units (RSUs) [Member], USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted Stock Units (RSUs) [Member]
Note K - Accounting for Stock-based Compensation (Details) - Restricted Stock Unit Activity [Line Items]
Non-vested RSUs, Shares	643,887	756,188	848,591	769,019
Non-vested RSUs, Weighted-Average Grant Date Fair Value	$ 31.10	$ 25.13	$ 24.32	$ 23.67
Non-vested RSUs, Aggregate Intrinsic Value	$ 26,386
Granted, Shares	265,811	229,574	374,868
Granted, Weighted-Average Grant Date Fair Value	$ 39.48	$ 27.02	$ 25.42
Vested, Shares	(333,321)	(288,258)	(230,632)
Vested, Weighted-Average Grant Date Fair Value	$ 24.73	$ 24.28	$ 24.66
Cancelled, Shares	(44,791)	(33,719)	(64,664)
Cancelled, Weighted-Average Grant Date Fair Value	$ 27.33	$ 24.86	$ 24.24
Restricted stock units expected to vest in the future	604,341
Restricted stock units expected to vest in the future	$ 31.10
Restricted stock units expected to vest in the future	$ 24,766

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Share based compensation arrangement by share based payment award equity instruments other than options non vested aggregate intrinsic value.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

-Section 50

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of fully vested and expected to vest options outstanding.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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