75000 - Document - Document and Entity Information link:presentationLink link:calculationLink link:definitionLink Reported Value of Equity Awards [Member] Reported value of equity awards. SCT Average Reported Value of Equity Awards Prior Years Year End Value Ascribed to Any Equity Awards For the Vesting Conditions Were Not Met And Awards Were Therefore Forfeited as of The End of or During the Year [Member] Prior year’s year end value ascribed to any equity awards for which the vesting conditions were not met (and awards were therefore forfeited) as of the end of or during the year. Subtract: the prior year's year end value ascribed to any equity awards for which the vesting conditions were not met (and awards were therefore forfeited) as of the end of or during the year Amendment Flag Year Over Year Change in Fair Value of All Equity Awards Granted in Prior Years And That Vested During the Year [Member] Year-over-year change in fair value of all equity awards granted in prior years and that vested during the year. Add: the positive or negative year-over-year change in fair value of all equity awards granted in prior years and that vested during the year, with the final value calculated as of the vesting date Document Type Entity Central Index Key Field [Member] Field. Field Sedky [Member] Sedky. Sedky Value of Dividends or other Earnings Paid on Equity Awards not Otherwise Reflected in Fair Value or Compensation [Member] Value of dividends or other earnings paid on equity awards not otherwise reflected in fair value or compensation. Average Value of Dividends or other Earnings Paid on Equity Awards not Otherwise Reflected in Fair Value or Total Compensation Advertising And Entertainment Peers [Member] Advertising and entertainment peers. Advertising and Entertainment Peers Digital Information Services And Research Peers [Member] Digital information services and research peers. Digital Information Services & Research Peers Cover [Abstract] Summary Compensation Table in Respect of All Equity Awards [Member] Summary compensation table in respect of all equity awards. Subtract: the amounts reported in the Summary Compensation Table in respect of all equity awards Year-End Fair Value of Equity Awards Granted in Year and that Unvested [Member] Year-end fair value of equity awards granted in year and that unvested. Average Year-End Fair Value of Equity Awards Granted in the Year and that are Unvested Prior Year-End Fair Value of Equity Awards that Failed to Meet Vesting Conditions in Year [Member] Prior year-end fair value of equity awards that failed to meet vesting conditions in year. Average Prior Year-End Fair Value of Equity Awards that Failed to Meet Vesting Conditions in the Year Equity Award Adjustments [Member] Equity award adjustments. Average Equity Award Adjustments Exhibition Peers [Member[ Exhibition peers. Exhibition Peers Fair Value as of Vesting Date of Equity Awards Granted and Vested in Year [Member] Fair value as of vesting date of equity awards granted and vested in year. Average Fair Value as of Vesting Date of Equity Awards Granted and Vested in the Year Year Over Year Change in Fair Value of All Equity Awards Granted in Prior Years and Remain Outstanding an Unvested as of the End of the Year [Member] Year-over-year change in fair value of all equity awards granted in prior years and remain outstanding an unvested as of the end of the year, with the value calculated as of year end. Add: the positive or negative year-over-year change in fair value of all equity awards granted in prior years and remain outstanding an unvested as of the end of the year, with the value calculated as of year end Entity Registrant Name Fair Value of All Equity Awards Granted During the Year [Member] Fair value of all equity awards granted during the year. Add: the fair value of all equity awards granted during the year that were outstanding and unvested as of the end of the year, with the value calculated as of the end of year end Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years that Unvested [Member] Year-over-year change in fair value of equity awards granted in prior years that unvested. Average Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years that are Unvested Business Services Peers [Member] Business services peers. Business Services Peers Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years that Vested in Year [Member] Year-over-year change in fair value of equity awards granted in prior years that vested in year. Average Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years that Vested in the Year