Stock-Based Compensation (Summary Of Stock Option Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares, Options outstanding at January 1	3,786,419
Shares, Granted	0
Shares issued upon exercise of employee stock options	(1,140,255)
Shares, Forfeited	(82,900)
Shares, Expired	(7,150)
Shares, Options outstanding at December 31	2,556,114
Shares, Options fully vested or expected to vest at December 31	2,543,874
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted average exercise price, Options outstanding at January 1	$ 19.12
Weighted average exercise price, Granted	$ 0.00
Weighted average exercise price, Exercised	$ 13.59
Weighted average exercise price, Forfeited	$ 25.15
Weighted average exercise price, Expired	$ 21.89
Weighted average exercise price, Options outstanding at December 31	$ 21.38
Weighted average exercise price, Options fully vested or expected to vest at December 31	$ 21.31