Income Taxes	3 Months Ended
Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Tax Cuts and Jobs Act On December 22, 2017, the Tax Cuts and Jobs Act (the "2017 Tax Act") was signed into law. The 2017 Tax Act includes a broad range of tax reform provisions affecting businesses, including lower corporate tax rates, changes in business deductions, and international tax provisions. In response to the 2017 Tax Act, the U.S. Securities and Exchange Commission staff issued Staff Accounting Bulletin No. 118 ("SAB 118") to address the application of U.S. GAAP in situations where a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the 2017 Tax Act. SAB 118 provides that the measurement period is complete when a company's accounting is complete and that measurement period shall not extend beyond one year from the enactment date. The Company completed the accounting for the effects of the 2017 Tax Act in the fiscal quarter ended December 31, 2018 and recognized an income tax benefit of $37.0 million related to a decrease in its tax on historical foreign earnings and profits through December 31, 2017 (the "transition tax"). This measurement period adjustment favorably impacted the Company's effective tax rate by 8.5% for the three months ended December 31, 2018. The Company expects to pay $182.6 million related to the transition tax, which is net of overpayments and tax credits, over a six-year period commencing in January 2021. There were no adjustments recorded to deferred income taxes related to the 2017 Tax Act during the three months ended December 31, 2018. Other Information The Company files income tax returns in U.S. federal and state jurisdictions as well as various foreign jurisdictions. As of December 31, 2018, the Company had unrecognized tax benefits, defined as the aggregate tax effect of differences between tax return positions and the benefits recognized in the Company’s financial statements, of $106.6 million ($81.7 million, net of federal benefit). If recognized, $63.4 million of these tax benefits would have reduced income tax expense and the effective tax rate. Included in this amount is $15.7 million of interest and penalties, which the Company records in Income Tax Expense (Benefit) in the Company's Consolidated Statements of Operations. In the three months ended December 31, 2018, unrecognized tax benefits decreased by $6.3 million. Over the next 12 months, it is reasonably possible that state tax audit resolutions and the expiration of statutes of limitations could result in a reduction of unrecognized tax benefits by approximately $4.5 million. The Company's effective tax rates were 9.4% and (140.1)% for the three months ended December 31, 2018 and 2017, respectively. The effective tax rate in the three months ended December 31, 2018 was primarily impacted by the $37.0 million decrease to the Company's transition tax related to the 2017 Tax Act. The effective tax rate in the three months ended December 31, 2017 was primarily impacted by the effect of the 2017 Tax Act. The Company's effective tax rates for both periods reported herein were favorably impacted by the Company's international businesses in Switzerland and Ireland, which have lower income tax rates, and the benefit from stock option exercises and restricted stock vesting.

Income Taxes

Tax Cuts and Jobs Act

On December 22, 2017, the Tax Cuts and Jobs Act (the "2017 Tax Act") was signed into law. The 2017 Tax Act includes a broad range of tax reform provisions affecting businesses, including lower corporate tax rates, changes in business deductions, and international tax provisions. In response to the 2017 Tax Act, the U.S. Securities and Exchange Commission staff issued Staff Accounting Bulletin No. 118 ("SAB 118") to address the application of U.S. GAAP in situations where a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the 2017 Tax Act. SAB 118 provides that the measurement period is complete when a company's accounting is complete and that measurement period shall not extend beyond one year from the enactment date.

The Company completed the accounting for the effects of the 2017 Tax Act in the fiscal quarter ended December 31, 2018 and recognized an income tax benefit of $37.0 million related to a decrease in its tax on historical foreign earnings and profits through December 31, 2017 (the "transition tax"). This measurement period adjustment favorably impacted the Company's effective tax rate by 8.5% for the three months ended December 31, 2018. The Company expects to pay $182.6 million related to the transition tax, which is net of overpayments and tax credits, over a six-year period commencing in January 2021.

There were no adjustments recorded to deferred income taxes related to the 2017 Tax Act during the three months ended December 31, 2018.

Other Information

The Company files income tax returns in U.S. federal and state jurisdictions as well as various foreign jurisdictions. As of December 31, 2018, the Company had unrecognized tax benefits, defined as the aggregate tax effect of differences between tax return positions and the benefits recognized in the Company’s financial statements, of $106.6 million ($81.7 million, net of federal benefit). If recognized, $63.4 million of these tax benefits would have reduced income tax expense and the effective tax rate. Included in this amount is $15.7 million of interest and penalties, which the Company records in Income Tax Expense (Benefit) in the Company's Consolidated Statements of Operations. In the three months ended December 31, 2018, unrecognized tax benefits decreased by $6.3 million. Over the next 12 months, it is reasonably possible that state tax audit resolutions and the expiration of statutes of limitations could result in a reduction of unrecognized tax benefits by approximately $4.5 million.

The Company's effective tax rates were 9.4% and (140.1)% for the three months ended December 31, 2018 and 2017, respectively. The effective tax rate in the three months ended December 31, 2018 was primarily impacted by the $37.0 million decrease to the Company's transition tax related to the 2017 Tax Act. The effective tax rate in the three months ended December 31, 2017 was primarily impacted by the effect of the 2017 Tax Act. The Company's effective tax rates for both periods reported herein were favorably impacted by the Company's international businesses in Switzerland and Ireland, which have lower income tax rates, and the benefit from stock option exercises and restricted stock vesting.