Reconciliation of Beginning and Ending Aggregate Carrying Amount of Asset Retirement Obligation (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Reconciliation of Changes in Asset Retirement Obligations [Line Items]
Balance at beginning of year	$ 615,545		$ 555,248
Accretion expense	39,341		37,701	[1]
Liabilities incurred	184,439		51,858
Revision of previous estimates	10,468		7,608
Liabilities settled	(40,434)		(32,088)	[2]
Changes due to translation of foreign currencies	6,579		(4,782)
Balance at end of year	751,583		615,545
Current portion of liability at end of year	(27,310)	[3]	0
Noncurrent portion of liability at end of year	$ 724,273		$ 615,545

[1] Includes $2,977 reclassified to discontinued operations associated with U.K. oil and gas production operations.

[2] Includes noncash settlements related to sale of assets in Spain in 2011.

[3] Included in Other Accrued Liabilities on Consolidated Balance Sheet.