Income Taxes	6 Months Ended
Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company's Provision for Income Taxes was $25,541 and $30,479 for the three and six months ended June 30, 2018, respectively, and $22,459 and $40,751 for the three and six months ended June 30, 2017, respectively. The effective tax rate was 24% and 14% for the three and six months ended June 30, 2018, respectively, and 46% and 25% for the three and six months ended June 30, 2017, respectively. In conjunction with the enactment of the Tax Cuts and Jobs Act on December 22, 2017, which reduced income tax rates in the U.S. in 2018 and future years, the Company's effective tax rate for the three and six months ended June 30, 2018 was reduced by 13 and 12 percentage points, respectively, before the impact of ASU 2016-09, "Improvements to Employee Share-Based Payment Accounting" ("ASU 2016-09"). The effective tax rate for the three and six months ended June 30, 2018 also reflects the application of ASU 2016-09, which was adopted effective January 1, 2017. ASU 2016-09 requires that the tax deduction associated with the appreciation in the Company's share price upon vesting of employee share-based awards above the original grant price be reflected in income tax expense. The application of 2016-09 resulted in excess tax benefits from the delivery of Class A common stock under share-based payment arrangements of $22,222 and $23,172 being recognized in the Company's Provision for Income Taxes for the six months ended June 30, 2018 and 2017, respectively, and resulted in a reduction in the effective tax rate of 10 and 14 percentage points for the six months ended June 30, 2018 and 2017, respectively. The effective tax rate for 2018 and 2017 also reflects the effect of certain nondeductible expenses, including expenses related to Class E, J, I-P and K-P LP Units and Class G and H LP Interests, as well as the noncontrolling interest associated with LP Units and other adjustments. On December 22, 2017, the SEC issued SAB 118 to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available or computed analysis in reasonable detail to complete the accounting for certain income tax effects of the Tax Cuts and Jobs Act. The Company recognized a provisional tax impact related to the re-measurement of net deferred tax assets, the write down of other comprehensive income related to certain foreign subsidiaries, the valuation allowance and effects of the mandatory deemed repatriation tax on undistributed earnings of foreign subsidiaries within its consolidated financial statements for the year ended December 31, 2017. The Company's estimated tax charge as a result of the Tax Cuts and Jobs Act could be subject to adjustments as the Company continues its analysis, which may be impacted by changes in interpretations and assumptions the Company has made in conjunction with the release of additional regulatory guidance that may be issued. There were no changes to the provisional amounts recognized in 2017; the Company expects to record any adjustments to the estimated tax impact associated with the Tax Cuts and Jobs Act in the period in which the items are recognized. Additionally, the Company expects to recognize the income tax effects associated with the new global intangible low-taxed income ("GILTI") provisions in the period incurred. For the three and six months ended June 30, 2018, no additional income tax expense associated with the GILTI provisions has been reported and it is not expected to be material to the Company’s effective tax rate for the year. The Company reported an increase in deferred tax assets of $130 associated with changes in Unrealized Gain (Loss) on Marketable Securities and an increase of $1,108 associated with changes in Foreign Currency Translation Adjustment Gain (Loss), in Accumulated Other Comprehensive Income (Loss) for the six months ended June 30, 2018. The Company reported a decrease in deferred tax assets of $205 associated with changes in Unrealized Gain (Loss) on Marketable Securities and a decrease of $629 associated with changes in Foreign Currency Translation Adjustment Gain (Loss), in Accumulated Other Comprehensive Income (Loss) for the six months ended June 30, 2017. As of June 30, 2018, the Company had no unrecognized tax benefits. The Company classifies interest relating to tax matters and tax penalties as a component of income tax expense in its Unaudited Condensed Consolidated Statements of Operations.

Income Taxes

The Company's Provision for Income Taxes was $25,541 and $30,479 for the three and six months ended June 30, 2018, respectively, and $22,459 and $40,751 for the three and six months ended June 30, 2017, respectively. The effective tax rate was 24% and 14% for the three and six months ended June 30, 2018, respectively, and 46% and 25% for the three and six months ended June 30, 2017, respectively. In conjunction with the enactment of the Tax Cuts and Jobs Act on December 22, 2017, which reduced income tax rates in the U.S. in 2018 and future years, the Company's effective tax rate for the three and six months ended June 30, 2018 was reduced by 13 and 12 percentage points, respectively, before the impact of ASU 2016-09, "Improvements to Employee Share-Based Payment Accounting" ("ASU 2016-09"). The effective tax rate for the three and six months ended June 30, 2018 also reflects the application of ASU 2016-09, which was adopted effective January 1, 2017. ASU 2016-09 requires that the tax deduction associated with the appreciation in the Company's share price upon vesting of employee share-based awards above the original grant price be reflected in income tax expense. The application of 2016-09 resulted in excess tax benefits from the delivery of Class A common stock under share-based payment arrangements of $22,222 and $23,172 being recognized in the Company's Provision for Income Taxes for the six months ended June 30, 2018 and 2017, respectively, and resulted in a reduction in the effective tax rate of 10 and 14 percentage points for the six months ended June 30, 2018 and 2017, respectively. The effective tax rate for 2018 and 2017 also reflects the effect of certain nondeductible expenses, including expenses related to Class E, J, I-P and K-P LP Units and Class G and H LP Interests, as well as the noncontrolling interest associated with LP Units and other adjustments.

On December 22, 2017, the SEC issued SAB 118 to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available or computed analysis in reasonable detail to complete the accounting for certain income tax effects of the Tax Cuts and Jobs Act. The Company recognized a provisional tax impact related to the re-measurement of net deferred tax assets, the write down of other comprehensive income related to certain foreign subsidiaries, the valuation allowance and effects of the mandatory deemed repatriation tax on undistributed earnings of foreign subsidiaries within its consolidated financial statements for the year ended December 31, 2017. The Company's estimated tax charge as a result of the Tax Cuts and Jobs Act could be subject to adjustments as the Company continues its analysis, which may be impacted by changes in interpretations and assumptions the Company has made in conjunction with the release of additional regulatory guidance that may be issued. There were no changes to the provisional amounts recognized in 2017; the Company expects to record any adjustments to the estimated tax impact associated with the Tax Cuts and Jobs Act in the period in which the items are recognized.

Additionally, the Company expects to recognize the income tax effects associated with the new global intangible low-taxed income ("GILTI") provisions in the period incurred. For the three and six months ended June 30, 2018, no additional income tax expense associated with the GILTI provisions has been reported and it is not expected to be material to the Company’s effective tax rate for the year.

The Company reported an increase in deferred tax assets of $130 associated with changes in Unrealized Gain (Loss) on Marketable Securities and an increase of $1,108 associated with changes in Foreign Currency Translation Adjustment Gain (Loss), in Accumulated Other Comprehensive Income (Loss) for the six months ended June 30, 2018. The Company reported a decrease in deferred tax assets of $205 associated with changes in Unrealized Gain (Loss) on Marketable Securities and a decrease of $629 associated with changes in Foreign Currency Translation Adjustment Gain (Loss), in Accumulated Other Comprehensive Income (Loss) for the six months ended June 30, 2017.

As of June 30, 2018, the Company had no unrecognized tax benefits.

The Company classifies interest relating to tax matters and tax penalties as a component of income tax expense in its Unaudited Condensed Consolidated Statements of Operations.