Income Taxes	6 Months Ended
Jun. 30, 2012
Income Taxes [Abstract]
Income Taxes	Income Taxes The Company’s effective income tax rate, including discrete items, was 38.6% and 34.7% for the six months ended June 30, 2012 and 2011, respectively. The effective income tax rate is based upon estimated income for the year, the estimated composition of the income in different jurisdictions and discrete adjustments, if any, in the applicable quarterly periods including settlements of tax audits or assessments, the resolution or identification of tax position uncertainties and acquisitions of other companies. The discrete items include the tax effect of disqualifying dispositions of incentive stock options and shares purchased under the Company's Employee Stock Purchase Plan. For the six months ended June 30, 2012, the effective income tax rate was higher than the federal statutory tax rate mainly due to the effect of accounting for stock-based compensation in accordance with the authoritative guidance for share-based payments and state income tax expense. For the six months ended June 30, 2011, the effective income tax rate was lower than the federal statutory tax rate mainly due to the composition of income in foreign jurisdictions that was taxed at lower rates compared to the statutory tax rates in the United States along with utilization of available research and development tax credits.

Income Taxes

6 Months Ended

Jun. 30, 2012

The Company’s effective income tax rate, including discrete items, was 38.6% and 34.7% for the six months ended June 30, 2012 and 2011, respectively. The effective income tax rate is based upon estimated income for the year, the estimated composition of the income in different jurisdictions and discrete adjustments, if any, in the applicable quarterly periods including settlements of tax audits or assessments, the resolution or identification of tax position uncertainties and acquisitions of other companies. The discrete items include the tax effect of disqualifying dispositions of incentive stock options and shares purchased under the Company's Employee Stock Purchase Plan. For the six months ended June 30, 2012, the effective income tax rate was higher than the federal statutory tax rate mainly due to the effect of accounting for stock-based compensation in accordance with the authoritative guidance for share-based payments and state income tax expense. For the six months ended June 30, 2011, the effective income tax rate was lower than the federal statutory tax rate mainly due to the composition of income in foreign jurisdictions that was taxed at lower rates compared to the statutory tax rates in the United States along with utilization of available research and development tax credits.