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Other Long-term Liabilities - Additional Information (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Non-current liabilities [abstract]    
Amount in escrow account $ 8.1 $ 10.4
Provision for maintenance 19.0 $ 22.4
Trust fund 3.0  
Provision for return condition 17.4  
Provision for Dismantaling $ 1.9