Income Taxes - Reconciliation between Provision for Income Taxes at Statutory Rate and Provision for Income Taxes at Effective Tax Rate (Parenthetical) (Detail) - USD ($) $ in Millions |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Income Tax Disclosure [Abstract] | ||
| Reduction to deferred income tax benefit and offsetting valuation allowance expense. | $ 31.0 | $ 32.8 |
| X | ||||||||||
- Definition Reduction to deferred income tax benefit and offsetting valuation allowance expense. No definition available.
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| X | ||||||||||
- References No definition available.
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