Income Taxes	9 Months Ended
Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	At the end of each interim period, we estimate our annual effective tax rate and apply that rate to our interim earnings. We also record the tax impact of certain unusual or infrequently occurring items, including changes in judgment about valuation allowances and the effects of changes in tax laws or rates, in the interim period in which they occur. The computation of the annual estimated effective tax rate at each interim period requires certain estimates and significant judgment including, but not limited to, the expected operating income for the year, projections of the proportion of income earned and taxed in state and foreign jurisdictions, permanent and temporary differences between book and taxable income, and the likelihood of recovering deferred tax assets generated in the current year. The accounting estimates used to compute the provision for income taxes may change as new events occur, additional information is obtained or as the tax environment changes. Our effective income tax rate for the nine months ended September 30, 2016 was 32.6%, compared with 34.8% for the comparable prior year period. The lower effective income tax rate for the nine months ended September 30, 2016 reflects the $11.5 million discrete item for excess tax benefits from stock-based payments related to the adoption of ASU 2016-09 as described in Note 3, "Financial Statement Information." The adoption of this accounting standard could result in fluctuations to the effective tax rate from period to period depending on the amount of excess tax benefits or deficiencies recognized. The other discrete tax items for the nine months ended September 30, 2016 and 2015 were immaterial. Our acquisitions completed during the first nine months of 2016, including our March 2016 acquisition of Rhiag and our April 2016 acquisition of PGW, contributed $29.7 million and $137.5 million of deferred tax assets and liabilities, respectively, relating to intangible assets; property, plant and equipment; and reserves, including pension and other post-retirement benefit obligations.

Income Taxes

9 Months Ended

Sep. 30, 2016

At the end of each interim period, we estimate our annual effective tax rate and apply that rate to our interim earnings. We also record the tax impact of certain unusual or infrequently occurring items, including changes in judgment about valuation allowances and the effects of changes in tax laws or rates, in the interim period in which they occur.

The computation of the annual estimated effective tax rate at each interim period requires certain estimates and significant judgment including, but not limited to, the expected operating income for the year, projections of the proportion of income earned and taxed in state and foreign jurisdictions, permanent and temporary differences between book and taxable income, and the likelihood of recovering deferred tax assets generated in the current year. The accounting estimates used to compute the provision for income taxes may change as new events occur, additional information is obtained or as the tax environment changes.

Our effective income tax rate for the nine months ended September 30, 2016 was 32.6%, compared with 34.8% for the comparable prior year period. The lower effective income tax rate for the nine months ended September 30, 2016 reflects the $11.5 million discrete item for excess tax benefits from stock-based payments related to the adoption of ASU 2016-09 as described in Note 3, "Financial Statement Information." The adoption of this accounting standard could result in fluctuations to the effective tax rate from period to period depending on the amount of excess tax benefits or deficiencies recognized. The other discrete tax items for the nine months ended September 30, 2016 and 2015 were immaterial.

Our acquisitions completed during the first nine months of 2016, including our March 2016 acquisition of Rhiag and our April 2016 acquisition of PGW, contributed $29.7 million and $137.5 million of deferred tax assets and liabilities, respectively, relating to intangible assets; property, plant and equipment; and reserves, including pension and other post-retirement benefit obligations.