Revenue Recognition - Additional Information (Detail)	12 Months Ended
Dec. 31, 2018 USD ($) Customer	Dec. 31, 2017 USD ($) Customer	Dec. 31, 2016 Customer
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Impairment losses on contract assets	$ 0	$ 0
Advance payments and deferred revenue	$ 240,000,000
Customer Concentration Risk [Member] \| Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Concentration risk, number of customers \| Customer	0	0	0
Concentration risk, percentage	10.00%	10.00%	10.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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