Loss Per Share (Schedule Of Loss 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
Earnings Per Share [Abstract]
Loss of basic loss per common share	$ (72,136)	$ (274,389)	$ (113,285)	$ (522,743)
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	$ (72,136)	$ (274,389)	$ (113,285)	$ (522,743)
Weighted shares of basic loss per common share	50,074	49,148	49,977	49,063
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	50,074	49,148	49,977	49,063
Per-Share amount of basic loss per common share	$ (1.44)	$ (5.58)	$ (2.27)	$ (10.66)
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	$ (1.44)	$ (5.58)	$ (2.27)	$ (10.66)