|
Property, Plant and Equipment (Additional Information) (Details) (USD $)
In Millions, unless otherwise specified |
Dec. 31, 2014
|
Dec. 31, 2013
|
|---|---|---|
| Oil and gas proved properties | ||
| Property, Plant and Equipment [Line Items] | ||
| Cumulative capitalized interest | $ 38.1 | $ 23.4 |
| 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 | $ 17.1 | $ 12.0 |