Total Unrecognized Compensation Cost, Net of Estimated Forfeitures (Detail) (Restricted Stock and Stock Units, USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Restricted Stock and Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost, net of estimated forfeitures	$ 51,877	$ 54,419	$ 62,928

The amount of expense, net of income tax, recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration