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Income Taxes (Schedule Of Effective Income Tax Rates Different From Statutory Federal Income Tax Rates) (Details) | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Income Tax Disclosure [Abstract] |  |  |
Statutory federal income tax rate | 21.00% | 35.00% | 35.00%
State income taxes, net of federal income tax benefit | 0.60% | 0.50% | 0.50%
Domestic production exclusion | 0.00% | (2.80%) | (2.70%)
Research tax credit | (0.80%) | (0.80%) | (0.80%)
Increase (reduction) in reserve for uncertain tax provisions | 0.10% | 0.10% | (0.20%)
Change in tax rate on deferred taxes | 0.50% | (7.20%) | 0.00%
Foreign tax credit | (0.10%) | (0.80%) | 0.00%
Foreign derived intangible income deduction | (4.60%) | 0.00% | 0.00%
Stock compensation | (1.00%) | (1.00%) | 0.00%
Other | 0.40% | 0.50% | 0.10%
Effective income tax rate | 16.10% | 23.50% | 31.90%

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