Income Taxes:

6 Months Ended

Jun. 30, 2020

Income Tax Disclosure [Abstract]

Income Tax Disclosure [Text Block]

Income Taxes

Income taxes were accrued at an estimated effective tax rate of 9% and 13% for the three and six months ended June 30, 2020, respectively, as compared to 17% and 12% for the three and six months ended June 30, 2019, respectively.

        The effective tax rate for the three and six months ended June 30, 2020 differs from the federal statutory rate of 21% principally because of the effect of the mix of U.S. and foreign incomes, state income taxes, global intangible low-taxed income ("GILTI"), foreign-derived intangible income ("FDII") and tax credits. The effective tax rate during the three and six months ended June 30, 2020 included a discrete tax benefit of $3.0 million and $3.5 million, respectively, related to the excess tax benefits recognized on stock option exercises and the vesting of restricted stock units during the period.

        The effective tax rate for the three and six months ended June 30, 2019 differs from the federal statutory rate of 21% principally because of the effect of the mix of U.S. and foreign incomes, state income taxes, GILTI and tax credits. The effective tax rate during the three and six months ended June 30, 2019 included a discrete tax benefit of $1.8 million and $7.4 million, respectively, related to the excess tax benefits recognized on stock option exercises and the vesting of restricted stock units during the period. In addition, the effective tax rate during the three and six months ended June 30, 2019 included a discrete tax provision of $9.5 million and $11.3 million as a result of a revaluation of the contingent consideration.