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Revenue - Additional Information (Detail)
3 Months Ended
Mar. 31, 2020
USD ($)
Category
Mar. 31, 2019
USD ($)
Dec. 31, 2019
USD ($)
Revenue [Line Items]      
Number of categories | Category 3    
Remaining performance obligations $ 0    
Recognized revenue 5,700,000 $ 6,900,000  
Other Than Maintenance Services      
Revenue [Line Items]      
Remaining performance obligations $ 14,300,000   $ 13,600,000