XML 113 R81.htm IDEA: XBRL DOCUMENT v3.3.1.900
Property, Plant and Equipment (Additional Information) (Details) - USD ($)
$ in Millions
Dec. 31, 2015
Dec. 31, 2014
Oil and gas proved properties    
Property, Plant and Equipment [Line Items]    
Cumulative capitalized interest $ 48.9 $ 38.1
Non-oil and natural gas equipment    
Property, Plant and Equipment [Line Items]    
Cumulative capitalized interest 4.3 4.3
Building and structures    
Property, Plant and Equipment [Line Items]    
Cumulative capitalized interest $ 20.4 $ 17.1