Stock Option And Deferred Compensation Plans (Summary Of Non-Vested Shares Of Restricted Common Stock Awards, Restricted Common Stock Units And Performance Stock Units) (Details) (USD $)	12 Months Ended			0 Months Ended	2 Months Ended	12 Months Ended
	Dec. 31, 2009	Dec. 31, 2011 Restricted Common Stock Awards [Member]	Dec. 31, 2011 Restricted Stock Units [Member]	Feb. 24, 2011 Performance Stock Units [Member]	Mar. 09, 2010 Performance Stock Units [Member]	Dec. 31, 2011 Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Non-vested shares as of January 1, 2011		35,626	855,360			129,860
Number of Shares, Shares granted			498,629	86,580	129,860	101,165
Number of Shares, Shares vested		(35,626)	(272,148)
Number of Shares, Shares canceled/expired/forfeited			(112,541)			(19,910)
Number of Shares, Non-vested shares as of December 31, 2011			969,300			211,115
Weighted Average Grant Date Fair value, Non-vested shares as of January 1, 2011		$ 32.06	$ 13.45			$ 17.22
Weighted Average Grant Date Fair Value, Shares granted	$ 15.43		$ 20.30			$ 20.30
Weighted Average Grant Date Fair Value, Shares vested		$ 32.06	$ 13.37
Weighted Average Grant Date Fair Value, Shares canceled/expired/forfeited			$ 16.04			$ 18.77
Weighted Average Grant Date Fair value, Non-vested shares as of December 31, 2011			$ 16.69			$ 18.55