Summary of Significant Accounting Policies Goodwill and Other Intangible Assets (Policies)	12 Months Ended
Dec. 31, 2012
Accounting Policies [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets We account for our business combinations using the acquisition accounting method, which requires us to determine the fair value of net assets acquired and the related goodwill and other intangible assets. Determining the fair value of assets acquired and liabilities assumed requires management's judgment and involves the use of significant estimates, including projections of future cash inflows and outflows, discount rates, asset lives and market multiples. Considering the characteristics of advertising, specialized marketing and communication services companies, our acquisitions usually do not have significant amounts of tangible assets, as the principal asset we typically acquire is creative talent. As a result, a substantial portion of the purchase price is allocated to goodwill and other intangible assets. We review goodwill and other intangible assets with indefinite lives not subject to amortization as of October 1^st each year and whenever events or significant changes in circumstances indicate that the carrying value may not be recoverable. We evaluate the recoverability of goodwill at a reporting unit level. We have 11 reporting units that were subject to the 2012 annual impairment testing. During 2012, our reporting unit structure changed due to the creation of a new reporting unit which had been previously included within an existing reporting unit, as well as the disposal of a reporting unit. Our annual impairment review as of October 1, 2012 did not result in an impairment charge at any of our reporting units. We review intangible assets with definite lives subject to amortization whenever events or circumstances indicate that a carrying amount of an asset may not be recoverable. Recoverability of these assets is determined by comparing the carrying value of these assets to the estimated undiscounted future cash flows expected to be generated by these assets. These assets are impaired when their carrying value exceeds their fair value. Impaired intangible assets with definite lives subject to amortization are written down to their fair value with a charge to expense in the period the impairment is identified. Intangible assets with definite lives are amortized on a straight-line basis with estimated useful lives generally between 7 and 15 years. Events or circumstances that might require impairment testing include the loss of a significant client, the identification of other impaired assets within a reporting unit, loss of key personnel, the disposition of a significant portion of a reporting unit, significant decline in stock price or a significant adverse change in business climate or regulations. In 2011, we adopted new authoritative guidance for goodwill which permits an entity to first assess qualitative factors to determine whether the fair value of a reporting unit is “more likely than not” less than its carrying value. Qualitative factors to consider may include macroeconomic conditions, industry and market considerations, cost factors that may have a negative effect on earnings, overall financial performance of the reporting unit, and other relevant entity-specific events such as changes in management, key personnel, strategy or clients, as well as pending litigation. If, after assessing the totality of events or circumstances such as those described above, an entity determines that it is "more likely than not" that the fair value of a reporting unit is less than its carrying value, then the entity is required to perform the first step of a two-step quantitative impairment test to identify and measure impairment, if necessary. Otherwise, no additional testing is required. For reporting units not included in the qualitative assessment, or for any reporting units identified in the qualitative assessment as "more likely than not" that the fair value is less than its carrying value, the first step of the quantitative impairment test is performed. For our annual impairment test, we compare the respective fair value of our reporting units' equity to the carrying value of their net assets. The first step is a comparison of the fair value of each reporting unit to its carrying value, including goodwill. The sum of the fair values of all our reporting units is reconciled to our current market capitalization plus an estimated control premium. Goodwill allocated to a reporting unit whose fair value is equal to or greater than its carrying value is not impaired, and no further testing is required. Should the carrying amount for a reporting unit exceed its fair value, then the first step of the quantitative impairment test is failed and the magnitude of any goodwill impairment is determined under the second step, which is a comparison of the implied fair value of a reporting unit's goodwill to its carrying value. The implied fair value of goodwill is the excess of the fair value of the reporting unit over its carrying value, excluding goodwill. Impaired goodwill is written down to its implied fair value with a charge to expense in the period the impairment is identified. The fair value of a reporting unit for 2012 and 2011 was estimated using a combination of the income approach, which incorporates the use of the discounted cash flow method, and the market approach, which incorporates the use of earnings and revenue multiples based on market data.

Goodwill and Other Intangible Assets

We account for our business combinations using the acquisition accounting method, which requires us to determine the fair value of net assets acquired and the related goodwill and other intangible assets. Determining the fair value of assets acquired and liabilities assumed requires management's judgment and involves the use of significant estimates, including projections of future cash inflows and outflows, discount rates, asset lives and market multiples. Considering the characteristics of advertising, specialized marketing and communication services companies, our acquisitions usually do not have significant amounts of tangible assets, as the principal asset we typically acquire is creative talent. As a result, a substantial portion of the purchase price is allocated to goodwill and other intangible assets.

We review goodwill and other intangible assets with indefinite lives not subject to amortization as of October 1^st each year and whenever events or significant changes in circumstances indicate that the carrying value may not be recoverable. We evaluate the recoverability of goodwill at a reporting unit level. We have 11 reporting units that were subject to the 2012 annual impairment testing. During 2012, our reporting unit structure changed due to the creation of a new reporting unit which had been previously included within an existing reporting unit, as well as the disposal of a reporting unit. Our annual impairment review as of October 1, 2012 did not result in an impairment charge at any of our reporting units.

We review intangible assets with definite lives subject to amortization whenever events or circumstances indicate that a carrying amount of an asset may not be recoverable. Recoverability of these assets is determined by comparing the carrying value of these assets to the estimated undiscounted future cash flows expected to be generated by these assets. These assets are impaired when their carrying value exceeds their fair value. Impaired intangible assets with definite lives subject to amortization are written down to their fair value with a charge to expense in the period the impairment is identified. Intangible assets with definite lives are amortized on a straight-line basis with estimated useful lives generally between 7 and 15 years. Events or circumstances that might require impairment testing include the loss of a significant client, the identification of other impaired assets within a reporting unit, loss of key personnel, the disposition of a significant portion of a reporting unit, significant decline in stock price or a significant adverse change in business climate or regulations.

In 2011, we adopted new authoritative guidance for goodwill which permits an entity to first assess qualitative factors to determine whether the fair value of a reporting unit is “more likely than not” less than its carrying value. Qualitative factors to consider may include macroeconomic conditions, industry and market considerations, cost factors that may have a negative effect on earnings, overall financial performance of the reporting unit, and other relevant entity-specific events such as changes in management, key personnel, strategy or clients, as well as pending litigation. If, after assessing the totality of events or circumstances such as those described above, an entity determines that it is "more likely than not" that the fair value of a reporting unit is less than its carrying value, then the entity is required to perform the first step of a two-step quantitative impairment test to identify and measure impairment, if necessary. Otherwise, no additional testing is required.

For reporting units not included in the qualitative assessment, or for any reporting units identified in the qualitative assessment as "more likely than not" that the fair value is less than its carrying value, the first step of the quantitative impairment test is performed. For our annual impairment test, we compare the respective fair value of our reporting units' equity to the carrying value of their net assets. The first step is a comparison of the fair value of each reporting unit to its carrying value, including goodwill. The sum of the fair values of all our reporting units is reconciled to our current market capitalization plus an estimated control premium. Goodwill allocated to a reporting unit whose fair value is equal to or greater than its carrying value is not impaired, and no further testing is required. Should the carrying amount for a reporting unit exceed its fair value, then the first step of the quantitative impairment test is failed and the magnitude of any goodwill impairment is determined under the second step, which is a comparison of the implied fair value of a reporting unit's goodwill to its carrying value. The implied fair value of goodwill is the excess of the fair value of the reporting unit over its carrying value, excluding goodwill. Impaired goodwill is written down to its implied fair value with a charge to expense in the period the impairment is identified.

The fair value of a reporting unit for 2012 and 2011 was estimated using a combination of the income approach, which incorporates the use of the discounted cash flow method, and the market approach, which incorporates the use of earnings and revenue multiples based on market data.