Stock-Based Compensation (Summary Of Stock Based Compensation Expense By Equity Award Type) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	$ 7,603	$ 3,227	$ 17,520	$ 10,516
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	3,575	3,088	9,523	10,008
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	267	139	788	508
Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	1,728		5,176
Performance Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	$ 2,033		$ 2,033