Asset Retirement Obligations (Tables)
|6 Months Ended|
Jun. 30, 2015
|Asset Retirement Obligation [Abstract]|
|Estimated Fair Value of Company's Asset Retirement Obligations||
Tabular disclosure of the changes in carrying amount of a liability for asset retirement obligations, for changes such as new obligations, changes in estimates of existing obligations, spending on existing obligations, property dispositions, and foreign currency translation.
Reference 1: http://www.xbrl.org/2003/role/presentationRef