Income Taxes	6 Months Ended
Mar. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes On December 22, 2017, the Tax Cuts and Jobs Act (the “Act”) was enacted in the United States. The Act reduced the top corporate U.S. federal statutory tax rate from 35% to 21% starting on January 1, 2018, resulting in a blended statutory tax rate for fiscal year filers. The Company’s blended federal statutory tax rate for fiscal 2018 is 24.6%. It also requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries, places limitations and exclusions on varied tax deductions and creates new taxes on certain foreign sourced earnings. The majority of the tax provisions, excluding the change in corporate tax rates, are effective for the first tax year beginning after January 1, 2018, which will be the Company’s taxable year beginning fiscal 2019. Given the significance of the legislation, the SEC staff issued Staff Accounting Bulletin No. 118 (SAB 118), which allows registrants to record provisional amounts during a one year “measurement period” similar to that used when accounting for business combinations. However, the measurement period is deemed to have ended earlier when the registrant has obtained, prepared and analyzed the information necessary to finalize its accounting. During the measurement period, impacts of the law are expected to be recorded at the time a reasonable estimate for all or a portion of the effects can be made, and provisional amounts can be recognized and adjusted as information becomes available, prepared or analyzed. SAB 118 summarizes a three-step process to be applied at each reporting period to account for and qualitatively disclose: (1) the effects of the change in tax law for which accounting is complete; (2) provisional amounts (or adjustments to provisional amounts) for the effects of the tax law where accounting is not complete, but that a reasonable estimate has been determined; and (3) a reasonable estimate cannot yet be made and therefore taxes are reflected in accordance with law prior to the enactment of the Act. As of March 30, 2018, we have not completed our accounting for the tax effects of the enactment of the Act. However, we have made a provisional estimate of the effects of the statutory tax rate reduction impact on our existing deferred tax balances and the one-time transition tax. We are not yet able to make a reasonable estimate on the other aspects of the Act and continue to account for those items based on our existing accounting under ASC 740, Income Taxes, and the provisions of the tax laws that were in effect immediately prior to enactment of the Act. For the deferred tax balances, we remeasured the U.S. deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future, which is generally 21%. The Company’s provisional remeasurement resulted in a $16.9 million net unfavorable discrete charge to income tax expense for the six months ended March 30, 2018. In addition, during the first quarter of fiscal 2018 the Company recorded a provisional valuation allowance with respect to certain foreign tax credit deferred tax assets as a result of the Tax Act in the amount of $52.5 million. We are still analyzing many aspects of the Act and refining our calculations, which could potentially affect the measurement of these balances or potentially give rise to new deferred tax assets and liabilities. The Act calls for a one-time tax on deemed repatriation of foreign earnings. This one-time transition tax is based on our total post-1986 earnings and profits (E&P) of certain of our foreign subsidiaries. We have made a provisional estimate of the transition tax. Based upon our review of the Company’s historical foreign tax credit position and post-1986 E&P, it is estimated at this time that the Company should not have any liability for the transition tax. However, we are still in the process of completing our calculation of the total post-1986 E&P for the newly acquired foreign subsidiaries related to the recent CH2M acquisition. Our estimate may change when we finalize the calculation of post-1986 foreign E&P previously deferred from U.S. federal taxation and finalize the amounts held in cash or other specified assets. The Company’s consolidated effective income tax rate for the three months ended March 30, 2018 increased to 57.5% from 27.0% for the corresponding period last year. The increase in the quarterly effective tax rate is primarily due to $40.6 million in discrete expense during the current year quarter from the provisional remeasurement of the U.S. deferred taxes which was primarily due to changes in estimate during the quarter as a result of updates in preliminary purchase price accounting for the CH2M acquisition that closed prior to the enactment of the Act. The Company’s consolidated effective income tax rate for the six months ended March 30, 2018 was 66.8%, an increase from 28.1% for the corresponding period last year. The year over year increase in the effective tax rate is due to $69.4 million in net discrete charges during the six month period, comprised of a $16.9 million detriment from the provisional remeasurement of the deferred tax items in the U.S., and a corresponding valuation allowance charge of $52.5 million. The amount of income taxes the Company pays is subject to ongoing audits by tax jurisdictions around the world. In the normal course of business, the Company is subject to examination by tax authorities throughout the world, including such major jurisdictions as Australia, Canada, India, the Netherlands, the United Kingdom and the United States. Our estimate of the potential outcome of any uncertain tax issue is subject to our assessment of the relevant risks, facts, and circumstances existing at the time. The Company believes that it has adequately provided for reasonably foreseeable outcomes related to these matters. However, future results may include favorable or unfavorable adjustments to our estimated tax liabilities in the period the assessments are made or resolved, which may impact our effective tax rate. It is reasonably possible that, during the next 12 months, we may realize a decrease in our uncertain tax positions of approximately $6.7 million as a result of concluding various tax audits and closing tax years. On December 15, 2017 the Company completed the acquisition of CH2M. For income tax purposes, the transaction was accounted for as a stock purchase. As a result of the acquisition, the Company adjusted its U.S. GAAP opening balance sheet of CH2M to reflect preliminary estimates of the fair value of the net assets acquired. For income tax purposes, the tax attributes and basis of net assets acquired carryover without any step-up to fair value. The Company has made preliminary estimates and recorded deferred taxes associated with the purchase accounting. It is expected that the Company will make adjustments to the purchase accounting over the relevant measurement period as allowed by ASC 805.

Income Taxes

On December 22, 2017, the Tax Cuts and Jobs Act (the “Act”) was enacted in the United States. The Act reduced the top corporate U.S. federal statutory tax rate from 35% to 21% starting on January 1, 2018, resulting in a blended statutory tax rate for fiscal year filers. The Company’s blended federal statutory tax rate for fiscal 2018 is 24.6%. It also requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries, places limitations and exclusions on varied tax deductions and creates new taxes on certain foreign sourced earnings. The majority of the tax provisions, excluding the change in corporate tax rates, are effective for the first tax year beginning after January 1, 2018, which will be the Company’s taxable year beginning fiscal 2019.

Given the significance of the legislation, the SEC staff issued Staff Accounting Bulletin No. 118 (SAB 118), which allows registrants to record provisional amounts during a one year “measurement period” similar to that used when accounting for business combinations. However, the measurement period is deemed to have ended earlier when the registrant has obtained, prepared and analyzed the information necessary to finalize its accounting. During the measurement period, impacts of the law are expected to be recorded at the time a reasonable estimate for all or a portion of the effects can be made, and provisional amounts can be recognized and adjusted as information becomes available, prepared or analyzed.

SAB 118 summarizes a three-step process to be applied at each reporting period to account for and qualitatively disclose: (1) the effects of the change in tax law for which accounting is complete; (2) provisional amounts (or adjustments to provisional amounts) for the effects of the tax law where accounting is not complete, but that a reasonable estimate has been determined; and (3) a reasonable estimate cannot yet be made and therefore taxes are reflected in accordance with law prior to the enactment of the Act.

As of March 30, 2018, we have not completed our accounting for the tax effects of the enactment of the Act. However, we have made a provisional estimate of the effects of the statutory tax rate reduction impact on our existing deferred tax balances and the one-time transition tax. We are not yet able to make a reasonable estimate on the other aspects of the Act and continue to account for those items based on our existing accounting under ASC 740, Income Taxes, and the provisions of the tax laws that were in effect immediately prior to enactment of the Act.

For the deferred tax balances, we remeasured the U.S. deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future, which is generally 21%. The Company’s provisional remeasurement resulted in a $16.9 million net unfavorable discrete charge to income tax expense for the six months ended March 30, 2018. In addition, during the first quarter of fiscal 2018 the Company recorded a provisional valuation allowance with respect to certain foreign tax credit deferred tax assets as a result of the Tax Act in the amount of $52.5 million. We are still analyzing many aspects of the Act and refining our calculations, which could potentially affect the measurement of these balances or potentially give rise to new deferred tax assets and liabilities.

The Act calls for a one-time tax on deemed repatriation of foreign earnings. This one-time transition tax is based on our total post-1986 earnings and profits (E&P) of certain of our foreign subsidiaries. We have made a provisional estimate of the transition tax. Based upon our review of the Company’s historical foreign tax credit position and post-1986 E&P, it is estimated at this time that the Company should not have any liability for the transition tax. However, we are still in the process of completing our calculation of the total post-1986 E&P for the newly acquired foreign subsidiaries related to the recent CH2M acquisition. Our estimate may change when we finalize the calculation of post-1986 foreign E&P previously deferred from U.S. federal taxation and finalize the amounts held in cash or other specified assets.

The Company’s consolidated effective income tax rate for the three months ended March 30, 2018 increased to 57.5% from 27.0% for the corresponding period last year. The increase in the quarterly effective tax rate is primarily due to $40.6 million in discrete expense during the current year quarter from the provisional remeasurement of the U.S. deferred taxes which was primarily due to changes in estimate during the quarter as a result of updates in preliminary purchase price accounting for the CH2M acquisition that closed prior to the enactment of the Act.

The Company’s consolidated effective income tax rate for the six months ended March 30, 2018 was 66.8%, an increase from 28.1% for the corresponding period last year. The year over year increase in the effective tax rate is due to $69.4 million in net discrete charges during the six month period, comprised of a $16.9 million detriment from the provisional remeasurement of the deferred tax items in the U.S., and a corresponding valuation allowance charge of $52.5 million.

The amount of income taxes the Company pays is subject to ongoing audits by tax jurisdictions around the world. In the normal course of business, the Company is subject to examination by tax authorities throughout the world, including such major jurisdictions as Australia, Canada, India, the Netherlands, the United Kingdom and the United States. Our estimate of the potential outcome of any uncertain tax issue is subject to our assessment of the relevant risks, facts, and circumstances existing at the time. The Company believes that it has adequately provided for reasonably foreseeable outcomes related to these matters. However, future results may include favorable or unfavorable adjustments to our estimated tax liabilities in the period the assessments are made or resolved, which may impact our effective tax rate.

It is reasonably possible that, during the next 12 months, we may realize a decrease in our uncertain tax positions of approximately $6.7 million as a result of concluding various tax audits and closing tax years.

On December 15, 2017 the Company completed the acquisition of CH2M. For income tax purposes, the transaction was accounted for as a stock purchase. As a result of the acquisition, the Company adjusted its U.S. GAAP opening balance sheet of CH2M to reflect preliminary estimates of the fair value of the net assets acquired. For income tax purposes, the tax attributes and basis of net assets acquired carryover without any step-up to fair value. The Company has made preliminary estimates and recorded deferred taxes associated with the purchase accounting. It is expected that the Company will make adjustments to the purchase accounting over the relevant measurement period as allowed by ASC 805.