Asset Retirement Obligation

9 Months Ended

Sep. 30, 2013

Asset Retirement Obligation [Abstract]

Changes in the carrying amounts of the asset retirement obligation associated with the Company’s oil and natural gas properties were as follows:



	Nine Months Ended			Year Ended
(Thousands of U.S. Dollars)	September 30, 2013			December 31, 2012
Balance, beginning of year	$	18,292		$	12,669
Settlements	(2,068		)	(404		)
Liability incurred	1,397			5,190
Liability assumed in a business combination	—			410
Foreign exchange	(23		)	45
Accretion	918			998
Revisions in estimated liability	1,872			(616		)
Balance, end of period	$	20,388		$	18,292

Asset retirement obligation - current	$	—		$	28
Asset retirement obligation - long-term	20,388			18,264
Balance, end of period	$	20,388		$	18,292

For the nine months ended September 30, 2013, settlements included cash payments of $0.9 million with the balance in accounts payable and accrued liabilities at September 30, 2013. Revisions to estimated liabilities relate primarily to changes in estimates of asset retirement costs and include, but are not limited to, revisions of estimated inflation rates, changes in property lives and the expected timing of settling the asset retirement obligation. At September 30, 2013, the fair value of assets that are legally restricted for purposes of settling the asset retirement obligation was $1.9 million (December 31, 2012 - $1.3 million).