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
	Mar. 31, 2016	Mar. 31, 2015
Basic Earnings (Loss) Per Share
Net income available to common shareholders	$ 49,972	$ 51,404
Weighted average common shares outstanding (in shares)	127,227	134,933
Net income per common share, basic (in dollars per share)	$ 0.39	$ 0.38
Diluted Earnings (Loss) Per Share
Net income available to common shareholders	$ 49,972	$ 51,404
Weighted average common shares outstanding (in shares)	127,227	134,933
Potentially dilutive shares from outstanding equity-based awards	630	811
Weighted average number of diluted common shares (in shares)	127,857	135,744
Net income per common share, diluted (in dollars per share)	$ 0.39	$ 0.38