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Commitments and Contingencies - Additional Information (Detail)
$ in Millions
3 Months Ended
Mar. 31, 2019
USD ($)
Commitments And Contingencies Disclosure [Line Items]  
Purchase obligation, 2019 $ 16.4
Purchase obligation, 2020 21.4
Purchase obligation, 2021 15.0
Purchase Obligations Satisfied 1.8
Actual Purchases Under Agreement 0.2
Chemical Supplier [Member]  
Commitments And Contingencies Disclosure [Line Items]  
Purchase obligation, 2019 $ 0.6