Income Taxes:	9 Months Ended
Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Income Taxes Income taxes were accrued at an estimated effective tax rate of (66)% and 25% for the nine months ended September 30, 2017 and 2016, respectively. Those rates differ from that computed at the federal statutory rate of 35%. The effective tax rate for the nine months ended September 30, 2017 differs from the federal statutory rate of 35% principally because of the effect the mix of U.S. and foreign incomes, state income taxes, tax credits and the impact of the gain on bargain purchase. The effective tax rate during the nine months ended September 30, 2017 also included a material tax benefit of $12.6 million related to the excess tax benefits recognized on stock option exercises and the vesting of restricted stock units during the period, which is treated as a discrete item and excluded from determining our annual estimated effective tax rate. The effective tax rate for the nine months ended September 30, 2016 differs from the federal statutory rate of 35% principally because of the effect of foreign and state income taxes, tax credits and deductions for domestic production activities. The effective tax rate during the nine months ended September 30, 2016 also included a material tax benefit of $6.6 million related to the excess tax benefits recognized on stock option exercises and the vesting of restricted stock units during the period, which is treated as a discrete item and excluded from determining our annual estimated effective tax rate.

Income Taxes

Income taxes were accrued at an estimated effective tax rate of (66)% and 25% for the nine months ended September 30, 2017 and 2016, respectively. Those rates differ from that computed at the federal statutory rate of 35%.

The effective tax rate for the nine months ended September 30, 2017 differs from the federal statutory rate of 35% principally because of the effect the mix of U.S. and foreign incomes, state income taxes, tax credits and the impact of the gain on bargain purchase. The effective tax rate during the nine months ended September 30, 2017 also included a material tax benefit of $12.6 million related to the excess tax benefits recognized on stock option exercises and the vesting of restricted stock units during the period, which is treated as a discrete item and excluded from determining our annual estimated effective tax rate.

The effective tax rate for the nine months ended September 30, 2016 differs from the federal statutory rate of 35% principally because of the effect of foreign and state income taxes, tax credits and deductions for domestic production activities. The effective tax rate during the nine months ended September 30, 2016 also included a material tax benefit of $6.6 million related to the excess tax benefits recognized on stock option exercises and the vesting of restricted stock units during the period, which is treated as a discrete item and excluded from determining our annual estimated effective tax rate.