Note J - Income Taxes (Details) - Effective Income Tax Rate Reconciliation	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Effective Income Tax Rate Reconciliation [Abstract]
Taxes at statutory rate	35.00%	35.00%	35.00%
State taxes, net of federal benefit	4.20%	4.20%	4.60%
Foreign tax rate differential and U.S. unrepatriated earnings	(0.60%)	(0.30%)	(0.30%)
Other permanent differences	2.00%	0.70%	0.80%
Prior year tax adjustments and changes in unrecognized tax benefits	(2.30%)	(2.10%)	(0.90%)
Tax credits	(0.70%)	(0.70%)	(0.70%)
	37.60%	36.80%	38.50%

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to revisions of previously reported income tax expense.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits.

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