Stock-Based Compensation (Summary Of Stock Option Plan Activity) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Stock-Based Compensation [Abstract]
Outstanding, beginning of period, Shares	2,715,430	2,843,909
Granted, Shares	517,500	297,000
Exercised, Shares	(33,224)	(117,714)
Forfeited or cancelled, Shares
Expired, Shares	(158,850)	(256,250)
Outstanding, end of period, Shares	3,040,856	2,766,945
Outstanding, beginning of period, Weighted Average Exercise Price	$ 38.57	$ 39.22
Granted, Weighted Average Exercise Price	$ 36.81	$ 46.47
Exercised, Weighted Average Exercise Price	$ 32.24	$ 33.17
Forfeited or cancelled, Weighted Average Exercise Price
Expired, Weighted Average Exercise Price	$ 44.04	$ 57.00
Outstanding, end of period, Weighted Average Exercise Price	$ 38.06	$ 38.61