Income Taxes (Details 2) (USD $) In Millions	Dec. 31, 2010	Dec. 31, 2009
Deferred tax assets:
Allowance for doubtful accounts	$ 17.7	$ 25.6
Net operating loss carryforwards and other tax attributes	34.8	24.6
Deferred compensation	5.6	3.4
Restricted stock	38.5	34.6
Accrued expenses	73.6	114.0
Other	3.4	2.9
Gross deferred tax assets	173.6	205.1
Less valuation allowance	(23.2)	(16.1)
Net deferred tax assets	150.4	189.0
Deferred tax liabilities:
Depreciation and property differences	(71.1)	(42.1)
Goodwill and customer contract amortization	(438.0)	(367.9)
Prepaids	(1.4)	(1.5)
Other	(2.8)	(4.1)
Gross deferred tax liabilities	(513.3)	(415.6)
Net deferred tax liabilities	$ (362.9)	$ (226.6)

Deferred tax liabilities Prepaids.

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The sum of the tax effects as of the balance sheet date of the amounts of all future tax deductions arising from temporary differences between tax basis and generally accepted accounting principles basis recognition of assets, liabilities, revenues and expenses, which can only be deducted for tax purposes when permitted under enacted tax laws ( before the valuation allowance, if any, to reduce such sum amount to net realizable value). Includes any tax benefit realized in deferred tax assets for significant impacts of tax planning strategies.

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For entities that net deferred tax assets and tax liabilities, represents the unclassified net amount of deferred tax assets and liabilities as of the balance sheet date, which result from applying the applicable enacted tax rate to net temporary differences and carryforwards pertaining to assets or liabilities. A temporary difference is a difference between the tax basis of an asset or liability and its carrying amount in the financial statements prepared in accordance with generally accepted accounting principles that will reverse in ensuing periods.

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The aggregate tax effects as of the balance sheet date of all future tax deductions arising from temporary differences between tax basis and generally accepted accounting principles basis recognition of assets, liabilities, revenues and expenses, which can only be deducted for tax purposes when permitted under enacted tax laws; net of deducting the allocated valuation allowance, if any, to reduce such amount to net realizable value.

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The sum of the tax effects as of the balance sheet date of the amount of excesses of tax deductions over gross income in a year which cannot be used on the tax returns in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset.

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The tax effect as of the balance sheet date of the amount of estimated future tax deductions arising from other temporary differences not otherwise specified in the taxonomy.

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The tax effect as of the balance sheet date of the amount of the estimated future tax deductions arising from employee compensation costs, which can only be deducted for tax purposes when actual costs are incurred, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken.

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The tax effect as of the balance sheet date of the amount of the estimated future tax deductions arising from share-based compensation costs, which can only be deducted for tax purposes when actual costs are incurred, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken.

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The tax effect as of the balance sheet date of the amount of the estimated future tax deductions arising from currently nondeductible expenses in accrued liabilities, which can only be deducted for tax purposes when such items are actually incurred, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken.

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The tax effect as of the balance sheet date of the amount of the estimated future tax deductions arising from estimated losses reflected in the allowance for doubtful accounts, which can only be deducted for tax purposes when actual bad debts are known, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken.

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The sum of the portions of deferred tax assets as of the balance sheet date for which, based on the weight of available evidence, it is more likely than not will not be realized through future reductions of tax-based income.

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The cumulative amount of all deferred tax liabilities, which result from applying the applicable tax rate to net taxable temporary differences pertaining to each jurisdiction to which the entity is obligated to pay income tax. A taxable temporary difference is a difference between the tax basis and the carrying amount of an asset or liability in the financial statements prepared in accordance with generally accepted accounting principles that will result in taxable amounts in one or more future periods.

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The cumulative amount of the estimated future tax effects attributable to the difference between the tax basis of goodwill and intangible assets and the basis of goodwill and intangible assets computed in accordance with generally accepted accounting principles. The difference in basis, whether due to amortization or other reasons, will increase future taxable income when such difference reverses.

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The cumulative amount of the estimated future tax effects attributable to other temporary differences not otherwise specified in this taxonomy that were expensed for tax purposes but capitalized in conformity with generally accepted accounting principles, or which were recognized as revenue under GAAP but not for tax purposes, which will reverse in future periods.

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The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the tax basis of capital assets and the basis of capital assets computed in accordance with generally accepted accounting principles. The difference in basis, attributable to different capitalization of costs, depreciation, or amortization methodologies, will increase future taxable income when such basis difference is realized. Capital assets include but are not limited to assets such as land, real estate, leasehold improvements, machinery and equipment and furniture and fixtures.

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