XML 116 R85.htm IDEA: XBRL DOCUMENT v3.19.3
Commitments and Contingencies (Details)
$ in Millions
12 Months Ended
Feb. 07, 2013
plaintiff
Dec. 31, 1994
USD ($)
Sep. 30, 2019
USD ($)
Dec. 31, 2018
USD ($)
Loss Contingencies [Line Items]        
Letter of credit amount outstanding     $ 29.2  
Collective-bargaining arrangement, percentage of participants     58.00%  
Collective-bargaining arrangement, percentage of participants expiring in 2018     2.00%  
Kansas Breach of Settlement Agreement        
Loss Contingencies [Line Items]        
Litigation settlement   $ 58.7    
Number of plaintiffs appealing dismissal | plaintiff 1      
Surety Bond        
Loss Contingencies [Line Items]        
Outstanding surety bond     $ 4.2 $ 2.7