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Description of Business and Summary of Significant Accounting Policies - Goodwill and Other Intangible Assets (Details) | 12 Months Ended
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Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items] |
Goodwill impairment test, income approach weight | 75.00%
Goodwill impairment test, market approach weight | 25.00%
Years forecasted in goodwill impairment income approach | 5 years
Minimum |
Finite-Lived Intangible Assets [Line Items] |
Long-term consolidated annual growth rate | 2.00%
Minimum | Customer relationships and contracts |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful life of intangible assets | 3 years
Minimum | Internally developed software |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful life of intangible assets | 3 years
Minimum | Other |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful life of intangible assets | 1 year
Maximum |
Finite-Lived Intangible Assets [Line Items] |
Long-term consolidated annual growth rate | 3.50%
Maximum | Customer relationships and contracts |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful life of intangible assets | 14 years
Maximum | Trade name |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful life of intangible assets | 20 years
Maximum | Internally developed software |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful life of intangible assets | 5 years
Maximum | Other |
Finite-Lived Intangible Assets [Line Items] |
Estimated useful life of intangible assets | 10 years

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- Definition The weight provided to the Income Approach in determining the fair value of goodwill for a given reporting unit as part of the test for impairment. + References No definition available. + Details
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- Definition The weight given the Market Approach in calculating the fair value of goodwill for a given reporting unit as part of the test for impairment. + References No definition available. + Details
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- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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