Income Taxes:	6 Months Ended
Income Taxes:	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Income Taxes Income taxes were accrued at an estimated effective tax rate of 18% and 16% for the three and six months ended June 30, 2021, respectively, as compared to 9% and 13% for the three and six months ended June 30, 2020, respectively. The effective tax rate for the three and six months ended June 30, 2021 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, 2021 included a discrete tax benefit of $0.4 million and $2.2 million, respectively, related to 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, 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, GILTI, 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 excess tax benefits recognized on stock option exercises and the vesting of restricted stock units during the period.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.