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Derivative Instruments - Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Derivatives, Fair Value [Line Items]      
Derivative liability $ (4.8)    
Realization of gain, net of taxes (2.5)    
Gas hedges      
Derivatives, Fair Value [Line Items]      
Net settlement of hedges 1.8 $ 15.9 $ (4.2)
NGL hedges      
Derivatives, Fair Value [Line Items]      
Net settlement of hedges 0.0 0.5 0.3
Crude Oil      
Derivatives, Fair Value [Line Items]      
Net settlement of hedges $ 0.0 $ 0.6 $ 0.9