Earnings Per Share (Computations Of Basic And Diluted EPS) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Earnings Per Share [Abstract]
Net income applicable to common shareholders	$ 14,865	$ 46,016	$ 125,233	$ 113,186
Less: Undistributed net income allocable to participating securities	(150)	(549)	(1,260)	(1,403)
Net income (loss) applicable to common shareholders	14,715	45,467	123,973	111,783
Weighted average number of shares outstanding - basic	104,256	104,700	104,450	104,616
Stock options, Shares	112	93	86	84
Undistributed earnings reallocated to participating securities, value	1	2	5	6
Convertible Preferred Stock	10	10	30	30
Convertible preferred stock, Shares	361	361	361	361
Net income per common share - Diluted	$ 14,726	$ 45,479	$ 124,008	$ 111,819
Weighted average number of shares outstanding, diluted, total	104,729	105,154	104,897	105,061