Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2011

Asset Retirement Obligation [Abstract]

Reconciliation of the Company's Asset Retirement Obligation

A reconciliation of the Company's liability, which is included in other liabilities, for the years ended December 31 was as follows:

	2011			2010
	(In thousands)
Balance at beginning of year	$	95,970		$	76,359
Liabilities incurred	3,870			8,608
Liabilities acquired	—			5,272
Liabilities settled	(10,418		)	(10,740		)
Accretion expense	4,466			3,588
Revisions in estimates	3,921			12,621
Other	342			262
Balance at end of year	$	98,151		$	95,970