Reconciliation of income tax computed at US Federal tax rates (Detail)	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax [Abstract]
Statutory Income Tax	35.00%	35.00%	35.00%
Foreign Rate Differential, Inclusive of Foreign Rate Changes	(2.20%)	(2.50%)	(4.00%)
Tax Credits	(1.60%)	(1.40%)	(4.50%)
Other Items, Net	(0.30%)	(1.10%)	(0.70%)
Effective Tax	30.90%	30.00%	25.80%

Income Tax [Abstract]

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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 applicable to statutory income tax expense (benefit) outside of the country of domicile.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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 tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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