Employee Retirement Obligations (Detail) (Chief Executive Officer, USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Chief Executive Officer
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred compensation plan and other benefits related to the Company's Chief Executive Officer	$ 73,155	$ 71,603

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant