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, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Basic Earnings (Loss) Per Share
Net income available to common shareholders	$ 57,898	$ 53,233	$ 107,870	$ 104,637
Weighted average common shares outstanding (in shares)	125,100	132,947	126,164	133,935
Net income per common share, basic (in dollars per share)	$ 0.46	$ 0.40	$ 0.85	$ 0.78
Diluted Earnings (Loss) Per Share
Net income available to common shareholders	$ 57,898	$ 53,233	$ 107,870	$ 104,637
Weighted average common shares outstanding (in shares)	125,100	132,947	126,164	133,935
Potentially dilutive shares from outstanding equity-based awards (in shares)	599	678	614	743
Weighted average number of diluted common shares (in shares)	125,699	133,625	126,778	134,678
Net income per common share, diluted (in dollars per share)	$ 0.46	$ 0.40	$ 0.85	$ 0.78