Income Taxes - Reconciliation of U.K. Statutory Federal Tax and Panama Statutory Federal Tax Rate to Consolidated Effective Tax Rates (Detail)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule Of Income Tax [Line Items]
Federal statutory rate	21.00%	35.00%
Goodwill impairment	(14.00%)
Non-Panama operations		16.00%	(14.00%)
Audit settlements and reserves		1.00%	14.00%
Other (primarily tax on unremitted earnings)	1.00%	1.00%	2.00%
Effective tax rate	(4.00%)	28.00%	51.00%
UK [Member]
Schedule Of Income Tax [Line Items]
Federal statutory rate	19.00%
Panama [Member]
Schedule Of Income Tax [Line Items]
Federal statutory rate		25.00%	25.00%
Domestic Country [Member]
Schedule Of Income Tax [Line Items]
Change in valuation allowance for deferred tax assets	(7.00%)	(18.00%)	49.00%
Foreign Country [Member]
Schedule Of Income Tax [Line Items]
Change in valuation allowance for deferred tax assets	(3.00%)	3.00%	(25.00%)

Schedule of income tax.

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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 attributable to income tax settlements. Including, but not limited to, domestic tax settlement, foreign tax settlement, state and local tax settlement, and other tax settlements.

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