Quarterly report pursuant to Section 13 or 15(d)

Accounts Receivable and Revenues from Contracts with Customers - Concentration Risk (Details)

v3.20.1
Accounts Receivable and Revenues from Contracts with Customers - Concentration Risk (Details)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2020
USD ($)
Customer
Mar. 31, 2019
USD ($)
Customer
Dec. 31, 2018
Dec. 31, 2019
USD ($)
Revenue | Customer Concentration Risk        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Number of major customers | Customer 4 3    
Revenues, major customers $ 66.5 $ 69.0    
Concentration risk, percentage 73.00% 66.00%    
Revenue | Customer Concentration Risk | Major Customer 1        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Revenues, major customers $ 22.6      
Concentration risk, percentage 25.00%      
Revenue | Customer Concentration Risk | Major Customer 2        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Revenues, major customers $ 15.7      
Concentration risk, percentage 17.00%      
Revenue | Customer Concentration Risk | Major Customer 3        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Revenues, major customers $ 15.7      
Concentration risk, percentage 17.00%      
Revenue | Customer Concentration Risk | Major Customer 4        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Revenues, major customers $ 12.5      
Concentration risk, percentage 14.00%      
Accounts Receivable | Credit Concentration Risk        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Concentration risk, percentage 82.00%   83.00%  
Accounts receivable, major customers $ 22.0     $ 52.7