Reconciliation of Beginning and Ending Aggregate Carrying Amount of Asset Retirement Obligation (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Reconciliation of Changes in Asset Retirement Obligations [Line Items]
Balance at beginning of year	$ 555,248		$ 476,938
Accretion expense	37,701		31,857	[1]	26,154	[1]
Liabilities incurred	51,858		59,605
Revision of previous estimates	7,608		14,170
Liabilities settled	(32,088)	[2]	(36,506)
Changes due to translation of foreign currencies	(4,782)		9,184
Balance at end of year	$ 615,545		$ 555,248		$ 476,938

[1] Reclassified to conform to current presentation.

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