Share-Based Compensation (Schedule Of Share-Based Compensation Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based compensation expense	$ 14,242	$ 11,176	$ 11,817
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based compensation expense	12,154	11,047	11,547
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based compensation expense	1,535
Restricted Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based compensation expense	401
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based compensation expense	$ 152	$ 129	$ 270