Supplemental Information	6 Months Ended
Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Information	Supplemental Information Accounts Payable, Accruals and Other Liabilities At June 30, 2019 and December 31, 2018, accruals and other liabilities included accrued media of $151,143 and $180,586, respectively; and also included amounts due to noncontrolling interest holders for their share of profits. See Note 9 of the Notes to the Unaudited Condensed Consolidated Financial Statements included herein for additional information regarding noncontrolling interest holders share of profits. Goodwill and Indefinite Lived Intangibles Goodwill and indefinite life intangible assets (trademarks) acquired as a result of a business combination which are not subject to amortization are tested for impairment annually as of October 1st of each year, or more frequently if indicators of potential impairment exist. For goodwill, impairment is assessed at the reporting unit level. Goodwill balances as of June 30, 2019 and December 31, 2018, were $743,582 and $740,955, respectively. Income Taxes Our tax provision for interim periods is determined using an estimated annual effective tax rate, adjusted for discrete items arising in interim periods. Income tax expense for the three months ended June 30, 2019 was $2,088 (on income of $9,215 resulting in an effective tax rate of 22.7%) compared to an expense of $1,977 (on income of $7,956 resulting in an effective tax rate of 24.8%) for the three months ended June 30, 2018. The change in the effective tax rate was primarily driven by the jurisdictional mix of earnings. Income tax expense for the six months ended June 30, 2019 was $2,835 (on income of $10,195 resulting in an effective tax rate of 27.8%) compared to a benefit of $6,353 (on a loss of $28,979 resulting in an effective tax rate of 21.9%) for the six months ended June 30, 2018. The change in the effective tax rate was primarily driven by the jurisdictional mix of earnings.

Supplemental Information

Accounts Payable, Accruals and Other Liabilities

At June 30, 2019 and December 31, 2018, accruals and other liabilities included accrued media of $151,143 and $180,586, respectively; and also included amounts due to noncontrolling interest holders for their share of profits. See Note 9 of the Notes to the Unaudited Condensed Consolidated Financial Statements included herein for additional information regarding noncontrolling interest holders share of profits.

Goodwill and Indefinite Lived Intangibles

Goodwill and indefinite life intangible assets (trademarks) acquired as a result of a business combination which are not subject to amortization are tested for impairment annually as of October 1st of each year, or more frequently if indicators of potential impairment exist. For goodwill, impairment is assessed at the reporting unit level. Goodwill balances as of June 30, 2019 and December 31, 2018, were $743,582 and $740,955, respectively.

Income Taxes

Our tax provision for interim periods is determined using an estimated annual effective tax rate, adjusted for discrete items arising in interim periods.

Income tax expense for the three months ended June 30, 2019 was $2,088 (on income of $9,215 resulting in an effective tax rate of 22.7%) compared to an expense of $1,977 (on income of $7,956 resulting in an effective tax rate of 24.8%) for the three months ended June 30, 2018. The change in the effective tax rate was primarily driven by the jurisdictional mix of earnings.

Income tax expense for the six months ended June 30, 2019 was $2,835 (on income of $10,195 resulting in an effective tax rate of 27.8%) compared to a benefit of $6,353 (on a loss of $28,979 resulting in an effective tax rate of 21.9%) for the six months ended June 30, 2018. The change in the effective tax rate was primarily driven by the jurisdictional mix of earnings.