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Concentrations of Credit Risk - Additional Information (Detail) - USD ($) | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Risks And Uncertainties [Abstract] |  |  |
Expense for bad debts | $ 5,683,000 | $ 0 | $ 0

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- Definition Amount of expense (reversal of expense) for expected credit loss on accounts receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(5)) -URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227 + Details
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- References No definition available. + Details
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