Income Taxes	3 Months Ended
Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Effective Tax Rate The effective income tax rate was 19.6% and (32.3)% during the quarters ended December 31, 2017 and 2016, respectively. The provision for income taxes during interim quarterly reporting periods is based on our estimates of the effective tax rates for the full fiscal year. The effective tax rate in any quarter can also be affected positively or negatively by adjustments that are required to be reported in the specific quarter of resolution. The effective tax rate for the three months ended December 31, 2017 was significantly impacted by recording the impact of the Tax Cuts and Jobs Act (the “Tax Act”), enacted on December 22, 2017 by the U.S. government. The Tax Act makes broad and complex changes to the U.S. tax code that will affect our fiscal year ended September 30, 2018, including, but not limited to, (1) reducing the U.S. federal corporate tax rate and (2) requiring a one-time transition tax on certain un-repatriated earnings of foreign subsidiaries that is payable over eight years. The Tax Act reduces the federal corporate tax rate to 21.0% effective January 1, 2018. In accordance with Section 15 of the Internal Revenue Code, we will utilize a blended rate of 24.5% for our fiscal 2018 tax year, by applying a prorated percentage of the number of days prior to and subsequent to the January 1, 2018 effective date. We recorded provisional charges for the re-measurement of the deferred tax assets of $5.6 million to our income tax expense related to long-term deferred tax assets and $1.3 million related to short-term deferred tax assets during the quarter ended December 31, 2017. The Deemed Repatriation Transition Tax (the “Transition Tax”) is a tax on previously untaxed accumulated earnings and profits (“E&P”) of certain of our foreign subsidiaries. To determine the amount of the Transition Tax, we must determine, in addition to other factors, the amount of post-1986 E&P of the relevant subsidiaries, as well as the amount of non-U.S. income taxes paid on such earnings. We are able to make a reasonable estimate and recorded a provisional Transition Tax obligation of $4.9 million. On December 22, 2017, the SEC issued Staff Accounting Bulletin (“SAB 118”), which provides guidance on accounting for tax effects of the Tax Act. SAB 118 provides a measurement period that should not extend beyond one year from the Tax Act enactment date for companies to complete the accounting under ASC 740. In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the Act for which the accounting under ASC 740 is complete. To the extent that a company’s accounting for certain income tax effects of the Tax Act is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate to be included in the financial statements. If a company cannot determine a provisional estimate to be included in the financial statements, it should continue to apply ASC 740 on the basis of the provision of the tax laws that were in effect immediately before the enactment of the Tax Act. While we are able to make reasonable estimates of the impact of the reduction in corporate rate and the deemed repatriation transition tax, the final impact of the Tax Act may differ from these estimates, due to, among other things, changes in our interpretations and assumptions, additional guidance that may be issued by the I.R.S., and actions we may take. We are continuing to gather additional information to determine the final impact. The total unrecognized tax benefit for uncertain tax positions is estimated to be approximately $6.1 million and $6.5 million at December 31, 2017 and September 30, 2017, respectively. We recognize interest expense related to unrecognized tax benefits and penalties as part of the provision for income taxes in our condensed consolidated statements of income and comprehensive income. We have accrued interest of $0.4 million related to unrecognized tax benefits as of December 31, 2017 and September 30, 2017.

Income Taxes

Effective Tax Rate

The effective income tax rate was 19.6% and (32.3)% during the quarters ended December 31, 2017 and 2016, respectively. The provision for income taxes during interim quarterly reporting periods is based on our estimates of the effective tax rates for the full fiscal year. The effective tax rate in any quarter can also be affected positively or negatively by adjustments that are required to be reported in the specific quarter of resolution.

The effective tax rate for the three months ended December 31, 2017 was significantly impacted by recording the impact of the Tax Cuts and Jobs Act (the “Tax Act”), enacted on December 22, 2017 by the U.S. government. The Tax Act makes broad and complex changes to the U.S. tax code that will affect our fiscal year ended September 30, 2018, including, but not limited to, (1) reducing the U.S. federal corporate tax rate and (2) requiring a one-time transition tax on certain un-repatriated earnings of foreign subsidiaries that is payable over eight years.

The Tax Act reduces the federal corporate tax rate to 21.0% effective January 1, 2018. In accordance with Section 15 of the Internal Revenue Code, we will utilize a blended rate of 24.5% for our fiscal 2018 tax year, by applying a prorated percentage of the number of days prior to and subsequent to the January 1, 2018 effective date. We recorded provisional charges for the re-measurement of the deferred tax assets of $5.6 million to our income tax expense related to long-term deferred tax assets and $1.3 million related to short-term deferred tax assets during the quarter ended December 31, 2017.

The Deemed Repatriation Transition Tax (the “Transition Tax”) is a tax on previously untaxed accumulated earnings and profits (“E&P”) of certain of our foreign subsidiaries. To determine the amount of the Transition Tax, we must determine, in addition to other factors, the amount of post-1986 E&P of the relevant subsidiaries, as well as the amount of non-U.S. income taxes paid on such earnings. We are able to make a reasonable estimate and recorded a provisional Transition Tax obligation of $4.9 million.

On December 22, 2017, the SEC issued Staff Accounting Bulletin (“SAB 118”), which provides guidance on accounting for tax effects of the Tax Act. SAB 118 provides a measurement period that should not extend beyond one year from the Tax Act enactment date for companies to complete the accounting under ASC 740. In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the Act for which the accounting under ASC 740 is complete. To the extent that a company’s accounting for certain income tax effects of the Tax Act is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate to be included in the financial statements. If a company cannot determine a provisional estimate to be included in the financial statements, it should continue to apply ASC 740 on the basis of the provision of the tax laws that were in effect immediately before the enactment of the Tax Act. While we are able to make reasonable estimates of the impact of the reduction in corporate rate and the deemed repatriation transition tax, the final impact of the Tax Act may differ from these estimates, due to, among other things, changes in our interpretations and assumptions, additional guidance that may be issued by the I.R.S., and actions we may take. We are continuing to gather additional information to determine the final impact.

The total unrecognized tax benefit for uncertain tax positions is estimated to be approximately $6.1 million and $6.5 million at December 31, 2017 and September 30, 2017, respectively. We recognize interest expense related to unrecognized tax benefits and penalties as part of the provision for income taxes in our condensed consolidated statements of income and comprehensive income. We have accrued interest of $0.4 million related to unrecognized tax benefits as of December 31, 2017 and September 30, 2017.