Earnings Per Common Share (Computation Of Basic And Diluted Net Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net income (loss)	$ 17,086	$ (22,182)	$ 48,890	$ 6,378
Basic earnings per common share, Income (Numerator)	$ 17,086	$ (22,182)	$ 48,890	$ 6,378
Basic earnings per common share, Shares (Denominator)	72,009	70,671	71,714	70,479
Basic earnings per common share (dollars per share)	$ 0.24	$ (0.31)	$ 0.68	$ 0.09
Effect of dilutive securities:
Stock options and restricted stock, Shares (Denominator)	682	0	667	734
Stock options and restricted stock (dollars per share)	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Diluted earnings per common share, Income (Numerator)	$ 17,086	$ (22,182)	$ 48,890	$ 6,378
Diluted earnings per common share, Shares (Denominator)	72,691	70,671	72,381	71,213
Diluted earnings per common share (dollars per share)	$ 0.24	$ (0.31)	$ 0.68	$ 0.09
Options outstanding to purchase common stock excluded from computation of diluted earnings per common share (shares)	597	909	925	827
Antidilutive securities excluded from earnings per share, average exercise price (dollars per share)	$ 30.03	$ 26.01	$ 29.33	$ 26.32