Note K - Accounting for Stock-based Compensation (Details) - Stock Options Outstanding, by Exercise Price Range (USD $)	12 Months Ended
Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted Average Remaining Contractual Term	10 years
Price Range 1 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower range	9.05
Range of Exercise Prices, Upper range	25.00
Number Outstanding (in Shares)	237,276
Weighted Average Remaining Contractual Term	5 years 127 days
Weighted Average Exercise Price	22.10
Number Exercisable (in Shares)	232,242
Weighted Average Exercise Price	22.10
Price Range 2 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower range	25.01
Range of Exercise Prices, Upper range	27.00
Number Outstanding (in Shares)	155,141
Weighted Average Remaining Contractual Term	7 years 14 days
Weighted Average Exercise Price	25.66
Number Exercisable (in Shares)	96,885
Weighted Average Exercise Price	25.66
Price Range 3 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower range	27.01
Range of Exercise Prices, Upper range	28.00
Number Outstanding (in Shares)	207,646
Weighted Average Remaining Contractual Term	8 years 76 days
Weighted Average Exercise Price	27.03
Number Exercisable (in Shares)	64,673
Weighted Average Exercise Price	27.03
Price Range 4 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower range	28.01
Range of Exercise Prices, Upper range	41.00
Number Outstanding (in Shares)	166,861
Weighted Average Remaining Contractual Term	9 years 76 days
Weighted Average Exercise Price	40.68
Price Range 5 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower range	9.05
Range of Exercise Prices, Upper range	41.00
Number Outstanding (in Shares)	766,924
Weighted Average Remaining Contractual Term	7 years 109 days
Weighted Average Exercise Price	28.20
Number Exercisable (in Shares)	393,800
Weighted Average Exercise Price	23.78

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

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Number of options outstanding, including both vested and non-vested options.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

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-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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-Publisher FASB

-Name Accounting Standards Codification

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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