v3.3.0.814
Related Party Agreements and Transactions - Receivables from Related Parties (Detail) - USD ($)
$ in Millions
Sep. 30, 2015
Dec. 31, 2014
Related Party Transaction [Line Items]    
Current receivables from related parties $ 54.9 $ 41.0
MPC [Member]    
Related Party Transaction [Line Items]    
Current receivables from related parties 54.3 40.5
Centennial [Member]    
Related Party Transaction [Line Items]    
Current receivables from related parties 0.5 0.3
Muskegon [Member]    
Related Party Transaction [Line Items]    
Current receivables from related parties $ 0.1 $ 0.2