XML 17 R58.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Cash and Marketable Securities - Components of Investments (Details) - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Cash and Cash Equivalents [Line Items]        
Cash & Cash Equivalents $ 94.8 $ 69.2 $ 54.4 $ 40.5
Restricted Cash 64.8 64.3    
Restricted Marketable Securities 76.1 62.0    
Total 235.7 195.5    
Cash        
Cash and Cash Equivalents [Line Items]        
Cash & Cash Equivalents 94.8 69.2    
Restricted Cash 64.8 64.3    
Restricted Marketable Securities 0.0 0.0    
Total 159.6 133.5    
Equity Securities        
Cash and Cash Equivalents [Line Items]        
Cash & Cash Equivalents 0.0 0.0    
Restricted Cash 0.0 0.0    
Restricted Marketable Securities 63.5 55.6    
Total 63.5 55.6    
Debt Securities        
Cash and Cash Equivalents [Line Items]        
Cash & Cash Equivalents 0.0 0.0    
Restricted Cash 0.0 0.0    
Restricted Marketable Securities 12.6 6.4    
Total $ 12.6 $ 6.4