Net Income Per Common Share (Schedule Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Basic Earnings (Loss) Per Share
Net income available to common shareholders	$ 53,233	$ 44,313	$ 104,637	$ 90,170
Weighted average common shares outstanding	132,947	138,991	133,935	138,961
Net income per common share, basic	$ 0.40	$ 0.32	$ 0.78	$ 0.65
Diluted Earnings (Loss) Per Share
Net income available to common shareholders	$ 53,233	$ 44,313	$ 104,637	$ 90,170
Weighted average common shares outstanding	132,947	138,991	133,935	138,961
Potentially dilutive shares from assumed exercise of securities or other contracts to purchase common stock	678	576	743	574
Weighted average number of diluted common shares	133,625	139,567	134,678	139,535
Net income per common share, diluted	$ 0.40	$ 0.32	$ 0.78	$ 0.65