Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2012

Asset Retirement Obligation [Abstract]

Reconciliation of the company's asset retirement obligation

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

	2012			2011
	(In thousands)
Balance at beginning of year	$	98,151		$	95,970
Liabilities incurred	6,523			3,870
Liabilities acquired	—			—
Liabilities settled	(10,472		)	(10,418		)
Accretion expense	4,266			4,466
Revisions in estimates	3,655			3,921
Other	422			342
Balance at end of year	$	102,545		$	98,151