Income Taxes - Reconciliation of Panama Statutory Federal Tax Rate to Consolidated Effective Tax Rate (Detail)			12 Months Ended
Dec. 22, 2017	Dec. 21, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Income Tax [Line Items]
Panama federal statutory rate	21.00%	35.00%	25.00%	25.00%	25.00%
Non-Panama operations			14.00%	(14.00%)	29.00%
Change in valuation allowance for deferred tax assets	21.00%
Audit settlements and reserves			1.00%	14.00%	9.00%
Other (primarily tax on unremitted earnings)			1.00%	2.00%	7.00%
Effective tax rate attributable to continuing operations			26.00%	51.00%	80.00%
Domestic Country [Member]
Schedule Of Income Tax [Line Items]
Change in valuation allowance for deferred tax assets			(18.00%)	49.00%	52.00%
Foreign Country [Member]
Schedule Of Income Tax [Line Items]
Change in valuation allowance for deferred tax assets			3.00%	(25.00%)	(42.00%)

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.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

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-Name Accounting Standards Codification
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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

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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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
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-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

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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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