XML 47 R32.htm IDEA: XBRL DOCUMENT v3.8.0.1
Acquisitions & Divestitures 2016 Permian Basin Acquisition (Details)
$ in Millions
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2017
USD ($)
Sep. 30, 2017
USD ($)
Sep. 30, 2016
USD ($)
a
Dec. 31, 2016
USD ($)
Business Acquisition [Line Items]        
Bargain purchase gain from acquisition   $ (0.4) $ 4.4  
2016 Permian Basin Acquisition [Member]        
Business Acquisition [Line Items]        
Payments for acquisitions   591.0    
Net acres | a     9,600  
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual $ 18.8 38.6    
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual $ 3.5 5.4    
Bargain purchase gain from acquisition   $ (0.4)   $ (18.2)