XML 39 R28.htm IDEA: XBRL DOCUMENT v3.20.2
Contract Balances - Additional Information (Detail) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Dec. 31, 2019
Contract With Customer Asset And Liability [Line Items]          
Revenue, Remaining performance obligation $ 173,600,000   $ 173,600,000    
Prepaid Expenses and Other Current Assets          
Contract With Customer Asset And Liability [Line Items]          
Assets impairment charges 0 $ 0 0 $ 0  
Contract assets 800,000   800,000   $ 1,200,000
Current Deferred Revenue and Advanced Payments          
Contract With Customer Asset And Liability [Line Items]          
Revenue recognized from beginning deferred revenue $ 53,900,000 $ 51,000,000.0 $ 123,200,000 $ 118,000,000