Income Taxes (Summary Of Income Tax Benefit (Provision)) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Taxes [Abstract]
U.S. Federal	$ 55,928	$ (1,212)	$ (691)
State and local	59,390	305	(2,390)
Total current	115,318	(907)	(3,081)
U.S. Federal	(3,325)	(32,670)	270,470
State and local	(18,678)	(7,798)	57,756
Total deferred	(22,003)	(40,468)	328,226
Income tax benefit (provision)	$ 93,315	$ (41,375)	$ 325,145