Earnings Per Share (Computations Of Basic And Diluted EPS) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Earnings Per Share [Abstract]
Net income applicable to common shareholders	$ 44,641	$ 41,313	$ 110,368	$ 67,170
Less: Undistributed net income allocable to participating securities	(449)	(514)	(1,111)	(850)
Net income (loss) applicable to common shareholders	44,192	40,799	109,257	66,320
Weighted average number of shares outstanding - basic	104,563	104,673	104,547	104,573
Stock options, Shares	118	106	104	90
Undistributed earnings reallocated to participating securities, value	2	3	5	4
Convertible preferred stock	10	10	20	20
Convertible preferred stock, Shares	361	361	361	361
Net income per common share - Diluted	$ 44,204	$ 40,812	$ 109,282	$ 66,344
Weighted average number of shares outstanding, diluted, total	105,042	105,140	105,012	105,024