Other Non-Current Liabilities

6 Months Ended

Jun. 30, 2011

Other Non-Current Liabilities

Other Non-Current Liabilities

4. Other Non-Current Liabilities

Other non-current liabilities consist of the following:

	June 30,		December 31,
	2011		2010
	(In thousands)
Abandonment obligations	$	40,641	$	40,444
Other	857		857
	$	41,498	$	41,301

Changes in abandonment obligations for the six months ended June 30, 2011 and 2010 are as follows:

	Six Months Ended
	June 30,
	2011			2010
	(In thousands)
Beginning of period	$	40,444		$	38,412
Additional abandonment obligations from new properties	863			993
Sales or abandonments of properties	(2,037		)	(1,113		)
Revisions of previous estimates	—			(320		)
Accretion expense	1,371			1,294
End of period	$	40,641		$	39,266

Our asset retirement obligation is measured using primarily Level 3 inputs.  The significant unobservable inputs to this fair value measurement include estimates of plugging, abandonment and remediation costs, inflation rate and well life.  The inputs are calculated based on historical data as well as current estimated costs.