Net Income (Loss) Per Share (Reconciliation Of Earnings Attributable To Common Stockholders, Basic And Diluted) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Statement Operating Activities Segment [Line Items]
Income (loss) from continuing operations attributable to parent	$ 101,128	$ 203,924
Income (loss) from discontinued operations, net of tax, attributable to parent	(465)	10,695
Income (loss) as reported	100,663	214,619
Participating basic earnings	(1,270)	(2,448)
Basic income attributable to common stockholders	99,393	212,171
Reallocation of participating earnings	35	71
Diluted income attributable to common stockholders	99,428	212,242
Continuing Operations [Member]
Statement Operating Activities Segment [Line Items]
Income (loss) from continuing operations attributable to parent	101,128	203,924
Participating basic earnings	(1,270)	(2,326)
Basic income attributable to common stockholders	99,858	201,598
Reallocation of participating earnings	35	68
Diluted income attributable to common stockholders	99,893	201,666
Discontinued Operations [Member]
Statement Operating Activities Segment [Line Items]
Income (loss) from discontinued operations, net of tax, attributable to parent	(465)	10,695
Participating basic earnings	0	(122)
Basic income attributable to common stockholders	(465)	10,573
Reallocation of participating earnings	0	3
Diluted income attributable to common stockholders	$ (465)	$ 10,576