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Transactions with Major Customers and Concentration of Credit Risk - Additional Information (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Concentration Risk [Line Items]      
Cash and cash equivalents in excess of FDIC limits $ 207.3    
Maximum      
Concentration Risk [Line Items]      
Receivables payment terms 30 days    
Sales Revenue Net | Customer Concentration Risk | Parent and Affiliates      
Concentration Risk [Line Items]      
Revenue with parent as percentage of total revenues 59.70% 49.90% 44.50%