Foreign Currency Sale Contracts (Detail) - Foreign Exchange Contract	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 EUR (€)	Sep. 30, 2016 CAD
Euros
Derivative [Line Items]
Total transaction amount	$ 118,000,000		$ 118,000,000		€ 100,000,000
Change in fair value gain (loss)	(1,000,000)		$ (2,000,000)	$ 10,000,000
Euros | Minimum
Derivative [Line Items]
Transaction Date Range			2014-05
Forward purchase date range			2017-05
Euros | Maximum
Derivative [Line Items]
Transaction Date Range			2016-01
Forward purchase date range			2018-01
Canadian Dollars
Derivative [Line Items]
Transaction Date Range			2014-11
Total transaction amount	$ 22,000,000		$ 22,000,000			CAD 25,000,000
Forward purchase date range			2016-11
Change in fair value gain (loss)		$ 2,000,000	$ (1,000,000)	$ 3,000,000