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Divestitures - Additional Information (Detail) - USD ($) | 3 Months Ended
--- | ---
Mar. 31, 2020 | Mar. 31, 2019
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items] |  |
Gain (loss) on divestitures and sale of investments |  | $ 20,054,000
Other Sales [Member] |  |
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items] |  |
Gain (loss) on divestitures and sale of investments | $ 0 | $ 18,400,000

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