Basis Of Presentation And Accounting Policies (Summary Of Restricted Stock Activity Outstanding) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Units, Balance at December 31, 2010	266,659
Number of Units, Granted	107,696
Number of Units, Vested	(313,921)
Number of Units, Forfeited	(22,619)
Number of Units, Balance at December 31, 2011	37,815	266,659
Weighted Average Grant Date Fair Value, Balance at December 31, 2010	$ 30.91
Weighted Average Grant Date Fair Value, Granted	$ 28.01	$ 27.86	$ 22.41
Weighted Average Grant Date Fair Value, Vested	$ 31.18
Weighted Average Grant Date Fair Value, Forfeited	$ 28.02
Weighted Average Grant Date Fair Value, Balance at December 31, 2011	$ 26.99	$ 30.91
Market Condition Non-Vested Restricted Stocks [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Units, Balance at December 31, 2010	562,531
Number of Units, Granted	154,424
Number of Units, Vested	(402,459)
Number of Units, Forfeited	(291,304)
Number of Units, Balance at December 31, 2011	23,192
Weighted Average Grant Date Fair Value, Balance at December 31, 2010	$ 23.17
Weighted Average Grant Date Fair Value, Granted	$ 21.10
Weighted Average Grant Date Fair Value, Vested	$ 23.26
Weighted Average Grant Date Fair Value, Forfeited	$ 22.55
Weighted Average Grant Date Fair Value, Balance at December 31, 2011	$ 15.69