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Reconciliation of Restricted Equity Securities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Jan. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |  |
Restricted equity securities | $ 55,868 |  |  |
Net unrealized loss recognized on restricted equity securities during the period | (12,987) | $ 0 | $ 0 |
Balance at end of period | 55,868 |  |  |
Long-term investments | Fair Value Measurements Recurring | Restricted equity securities |  |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |  |
Restricted equity securities | 55,868 |  |  | $ 68,855
Net unrealized loss recognized on restricted equity securities during the period | (12,987) |  |  |
Balance at end of period | $ 55,868 |  |  | $ 68,855

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- Definition Amount of restricted investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 30 -Section 50 -Paragraph 1A -Subparagraph (b)(1)(i) -URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729 + Details
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- Definition Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=116654751&loc=SL75117546-209714 + Details
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