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Equity Investment - Narrative (Detail) - USD ($)
$ in Thousands
1 Months Ended 3 Months Ended 6 Months Ended
Jun. 30, 2020
Mar. 31, 2020
Oct. 31, 2016
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Schedule of Equity Method Investments [Line Items]              
Non-cash impairment charge       $ 0 $ 0 $ 0 $ 76,800
Proceeds from sale of equity investment           $ 0 10,000
October 2016 Investment | Variable Interest Entity, Not Primary Beneficiary              
Schedule of Equity Method Investments [Line Items]              
Percentage of equity interest held 10.00%   10.00%        
Equity investments     $ 10,000        
Non-cash impairment charge   $ 5,300          
Proceeds from sale of equity investment $ 10,000            
Gain on sale of investment         $ 5,300   $ 5,300