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Contract Balances - Additional Information (Detail) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Dec. 31, 2019
Contract With Customer Asset And Liability [Line Items]          
Revenue, Remaining performance obligation $ 172,500,000   $ 172,500,000    
Prepaid Expenses and Other Current Assets          
Contract With Customer Asset And Liability [Line Items]          
Assets impairment charges 0 $ 0 0 $ 0  
Contract assets 1,100,000   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 $ 37,300,000 $ 36,100,000 $ 160,500,000 $ 154,100,000