Income Taxes - Income Tax Rate Reconciliation (Details)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Rate Reconciliation [Abstract]
Provision at the U.S. federal statutory rate	34.00%	34.00%	34.00%
State taxes, net of federal benefit	0.00%	2.40%	5.20%
Foreign tax rate differential	(0.20%)	0.00%	0.60%
Valuation allowance	10.20%	(42.70%)	(72.30%)
Federal tax rate change	(43.90%)	0.00%	0.00%
Other true up	(0.00%)	(0.60%)	(7.80%)
Intangible assets impairment and other non-deductibles	(1.80%)	0.00%	(2.20%)
Other	2.10%	(4.10%)	(1.10%)
Income tax benefit (expense) effective rate	0.40%	(11.00%)	(43.60%)

Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses And Other Non-Deductibles, Percent

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Effective Income Tax Rate Reconciliation, Other True Up, Percent

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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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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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