| **Income Taxes - Textual (Details) - USD ($) $ in Millions**                                         | 3 Months Ended | 6 Months Ended |        |
|------------------------------------------------------------------------------------------------------|----------------|----------------|--------|
||
| **Income Tax Contingency [Line Items]**                                                              |           |           |   |   |   |
| Provision for income tax expense                                                                     | $ 42.4         | $ 32.2         | $ 82.1 | $ 62.5 |   |
| Net Deferred Tax Assets, Total                                                                       | 115.5          |           | 115.5  |   |   |
| Deferred Tax Assets, Valuation Allowance                                                             | 27.6           |           | 27.6   |   |   |
| Gross Operating Loss Carryforwards                                                                   | 72.0           |           | 72.0   |   |   |
| Employee Service Share-based Compensation, Tax Benefit from Compensation Expense                     |           |           | 15.5   |   |   |
| Gross Unrecognized Tax Benefits                                                                      | 2.8            |           | 2.8    |   | $ 2.9 |
| Unrecognized Tax Benefits that Would Impact Effective Tax Rate                                       | 2.8            |           | 2.8    |   | $ 2.9 |
| Federal                                                                                              |           |           |   |   |   |
| **Income Tax Contingency [Line Items]**                                                              |           |           |   |   |   |
| Deferred Tax Assets, Net Operating Loss Carryforwards                                                | 25.1           |           | 25.1   |   |   |
| Tax Credit Carryforward, Amount                                                                      | 15.8           |           | 15.8   |   |   |
| Minimum [Member]                                                                                     |           |           |   |   |   |
| **Income Tax Contingency [Line Items]**                                                              |           |           |   |   |   |
| Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit | 0.4            |           | 0.4    |   |   |
| Maximum [Member]                                                                                     |           |           |   |   |   |
| **Income Tax Contingency [Line Items]**                                                              |           |           |   |   |   |
| Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit | $ 2.6          |           | $ 2.6  |   |   |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
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No definition available.
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.
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| - Definition
Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.
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| - Definition
The amount of the unrecognized tax benefit of a position taken for which it is reasonably possible that the total amount thereof will significantly increase or decrease within twelve months of the balance sheet date.
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| - Definition
The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.
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| - Definition
Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.
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| - Definition
The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.
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