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Revenue Recognition - Additional Information (Detail) | 12 Months Ended
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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%

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