Share Based Compensation (Schedule Of Changes In The Number Of Shares Of Restricted Stock And Restricted Stock Units) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share Based Compensation [Abstract]
Shares, Outstanding, Beginning balance	1,250	4,015	3,225
Weighted Average Grant Date Fair Value, Outstanding, Beginning of balance	$ 21.93	$ 4.41	$ 2.17
Shares, Granted	261	1,475	853
Weighted Average Grant Date Fair Value, Granted	$ 31.08	$ 22.68	$ 11.35
Shares, Cancelled	(50)	(263)	(63)
Weighted Average Grant Date Fair Value, Cancelled	$ 21.00	$ 15.24	$ 14.00
Shares, Sold/issued	(621)	(3,977)
Weighted Average Grant Date Fair Value, Sold/issued	$ 23.12	$ 4.40
Shares, Outstanding, Ending balance	840	1,250	4,015
Weighted Average Grant Date Fair Value, Outstanding, Ending balance	$ 23.15	$ 21.93	$ 4.41