Net Income Per Limited Partner Unit (Schedule of Net Income In Excess Of Distribution) (Details) - Jun. 30, 2015 - USD ($)
$ in Millions
Total
Total
Schedule of Undistributed Net Income [Line Items]    
Net Income (Loss) Allocated to Limited Partners $ 16.3 $ 29.6
Incentive Distribution, Distribution 0.0 0.0
Undistributed Earnings, Basic (0.6) 3.5
Common Units [Member]    
Schedule of Undistributed Net Income [Line Items]    
Net Income (Loss) Allocated to Limited Partners 9.0 16.1
Distribution Made to Limited Partner, Cash Distributions Declared 9.0 13.9
Undistributed Earnings, Basic 0.0 2.2
Subordinated Units [Member]    
Schedule of Undistributed Net Income [Line Items]    
Net Income (Loss) Allocated to Limited Partners 7.3 13.5
Distribution Made to Limited Partner, Cash Distributions Declared 7.9 12.2
Undistributed Earnings, Basic $ (0.6) $ 1.3