Income Taxes - Schedule of Reconciliation of U.S. Federal Statutory Income Tax Rate to Effective Tax Rates (Detail)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
U.S. federal statutory income tax rate	35.00%	35.00%	35.00%
U.S. tax reform	43.40%
Foreign source income not subject to U.S. income tax	(4.20%)	(9.30%)	419.40%
Change in U.S. federal valuation allowance	(3.40%)	(3.60%)	5477.00%
Share-based incentive compensation	(4.00%)
Foreign taxes	(0.20%)	(0.10%)	(361.60%)
State and local taxes	2.40%	3.00%	522.20%
Income of non-controlling interests	(0.30%)	(0.30%)	13.80%
Other, net	(0.20%)	(0.80%)	(31.50%)
Effective income tax rate	68.50%	23.90%	6074.30%

Effective income tax rate reconciliation foreign source income loss not subject to domestic tax.

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

+ References

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-Publisher FASB
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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.

+ References

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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 noncontrolling interest income (loss) exempt from income taxes.

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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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