Summary Of Significant Accounting Policies (Computations Of Basic And Diluted EPS) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Earnings Per Share
Net income (loss) applicable to common shareholders	$ 16,753	$ 46,016	$ 41,313	$ 25,857	$ (49,821)	$ 26,161	$ (85,551)	$ (17,891)	$ 129,939	$ (127,102)	$ 101,867
Less: Undistributed net income allocable to participating securities									(1,599)		(1,436)
Undistributed net income (loss) applicable to common shareholders									128,340	(127,102)	100,431
(Income) loss from discontinued operations											(9,581)
Add: Undiscounted net income from discontinued operations allocable to participating securities											135
Income (loss) per common share - continuing operations									128,340	(127,102)	90,985
Weighted average number of shares outstanding - basic									104,528	103,857	99,136
Stock options, Shares									64		28
Undistributed earnings reallocated to participating securities, value									7		80
Convertible Senior Notes, Value
Convertible Senior Notes, Shares
Convertible preferred stock, Income									40		748
Shares to be included in diluted shares outstanding amount									361		6,556
Income (loss) per common share - continuing operations									128,387	(127,102)	91,813
Income (loss) per common share - discontinued operations											9,581
Net income (loss) per common share - Diluted									$ 128,387	$ (127,102)	$ 101,394
Weighted Average Number of Shares Outstanding, Diluted, Total									104,953	103,857	105,720