Quarterly report pursuant to Section 13 or 15(d)

Accounts Receivable and Revenues from Contracts with Customers - Additional Information (Details)

v3.10.0.1
Accounts Receivable and Revenues from Contracts with Customers - Additional Information (Details)
$ in Millions
9 Months Ended 12 Months Ended
Sep. 30, 2018
USD ($)
Customer
Sep. 30, 2017
USD ($)
Customer
Dec. 31, 2017
USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]      
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification $ 2.7    
Sales Revenue | Customer Concentration Risk [Member]      
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Number of major customers | Customer 3 2  
Revenues, major customers $ 254.5 $ 85.9  
Concentration risk, percentage 81.00% 82.00%  
Sales Revenue | Customer Concentration Risk [Member] | Major Customer 1      
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Revenues, major customers $ 126.6    
Concentration risk, percentage 40.00%    
Sales Revenue | Customer Concentration Risk [Member] | Major Customer 2      
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Revenues, major customers $ 65.9    
Concentration risk, percentage 21.00%    
Sales Revenue | Customer Concentration Risk [Member] | Major Customer 3      
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Revenues, major customers $ 62.0    
Concentration risk, percentage 20.00%    
Accounts Receivable | Credit Concentration Risk      
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Concentration risk, percentage 51.00%   82.00%
Accounts receivable, major customers $ 32.9   $ 32.1