Loss Per Share (Schedule Of Loss Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Loss of basic loss per common share	$ (24,022)	$ (205,281)	$ (137,307)	$ (728,024)
Income of effect of dilutive stock options, restricted stock, and stock appreciation rights (SARs)	0	0	0	0
Loss of diluted loss per common share	$ (24,022)	$ (205,281)	$ (137,307)	$ (728,024)
Weighted shares of basic loss per common share	50,081	49,155	50,012	49,094
Weighted shares of effect of dilutive stock options, restricted stock, and stock appreciation rights (SARs)	0	0	0	0
Weighted shares of diluted loss per common share	50,081	49,155	50,012	49,094
Per-Share amount of basic loss per common share	$ (0.48)	$ (4.18)	$ (2.75)	$ (14.83)
Per-Share amount of effect of dilutive stock options, restricted stock, and stock appreciation rights (SARs)	0.00	0.00	0.00	0.00
Per-Share amount of diluted loss per common share	$ (0.48)	$ (4.18)	$ (2.75)	$ (14.83)