XML 60 R46.htm IDEA: XBRL DOCUMENT v3.20.4
Contract Balances - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Contract With Customer Asset And Liability [Line Items]      
Revenue, Remaining performance obligation $ 205,900    
Prepaid Expenses and Other Current Assets      
Contract With Customer Asset And Liability [Line Items]      
Assets impairment charges 0 $ 0 $ 0
Contract assets 1,100,000 1,200,000  
Current Deferred Revenue and Advanced Payments      
Contract With Customer Asset And Liability [Line Items]      
Revenue recognized from beginning deferred revenue $ 182,600,000 $ 174,700,000 $ 194,600,000