Income Taxes - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Tax reserve	$ 19.3
Interest associated with uncertain tax positions	3.7
Decrease in income taxes	$ 5.2
Effective tax rate	24.40%	37.20%

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible alternative minimum tax credit carryforwards.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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The increase (decrease) during the reporting period in the amounts payable to taxing authorities for taxes that are based on the reporting entity's earnings, net of amounts receivable from taxing authorities for refunds of overpayments or recoveries of income taxes, and in deferred and other tax liabilities and assets.

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Amount of interest expense accrued for an underpayment of income taxes.

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