v3.10.0.1
Leases (Narrative) (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2018
USD ($)
mi
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Operating Leases [Line Items]      
Operating Leases, Future Minimum Payments Due, Next Twelve Months $ 33.8    
Operating Leases, Income Statement, Contingent Revenue 51.8 $ 24.9  
Total rent expense 42.1 $ 34.8 $ 30.2
Operating Leases, Future Minimum Payments, Due in Two Years 32.3    
Operating Leases, Future Minimum Payments, Due in Three Years 30.2    
Operating Leases, Future Minimum Payments, Due in Four Years 27.4    
Operating Leases, Future Minimum Payments, Due in Five Years 26.7    
Operating Leases, Future Minimum Payments, Due Thereafter $ 132.2    
Texas and New Mexico Pipeline (Leased) [Member]      
Operating Leases [Line Items]      
Pipeline, Length | mi 40    
Seabrook Logistics, LLC [Member] | Equity Method Investee [Member]      
Operating Leases [Line Items]      
Operating Leases, Future Minimum Payments Due, Next Twelve Months $ 11.0    
Total rent expense 10.6    
Operating Leases, Future Minimum Payments, Due in Two Years 11.0    
Operating Leases, Future Minimum Payments, Due in Three Years 9.4    
Operating Leases, Future Minimum Payments, Due in Four Years 6.6    
Operating Leases, Future Minimum Payments, Due in Five Years 6.6    
Operating Leases, Future Minimum Payments, Due Thereafter $ 37.5