XML 96 R72.htm IDEA: XBRL DOCUMENT v3.20.1
Commitments and Contingencies (Details)
$ in Millions
3 Months Ended 12 Months Ended
Feb. 07, 2013
plaintiff
Mar. 31, 2020
USD ($)
Dec. 31, 1994
USD ($)
Dec. 31, 2019
USD ($)
Loss Contingencies [Line Items]        
Collective-bargaining arrangement, percentage of participants   48.00%    
Collective-bargaining arrangement, percentage of participants expiring in 2020   12.00%    
Kansas Breach of Settlement Agreement        
Loss Contingencies [Line Items]        
Litigation settlement     $ 58.7  
Number of plaintiffs appealing dismissal | plaintiff 1      
Employment Putative Class Action        
Loss Contingencies [Line Items]        
Litigation settlement   $ 2.5    
Surety Bond        
Loss Contingencies [Line Items]        
Outstanding surety bond   4.3   $ 4.3
2020 Senior Unsecured Revolving Credit Facility | Revolving Credit Facility | Line of Credit        
Loss Contingencies [Line Items]        
Letter of credit amount outstanding   $ 22.8    
2018 Senior Unsecured Revolving Credit Facility | Revolving Credit Facility | Line of Credit        
Loss Contingencies [Line Items]        
Letter of credit amount outstanding       $ 23.0