Basis Of Presentation And Significant Accounting Policies (Schedule Of Calculations Of Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	7 Months Ended		12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011	May 31, 2010	May 31, 2009
Basis Of Presentation And Significant Accounting Policies [Abstract]
Net income (loss)	$ (5,565)	$ 30,488	$ 73,609	$ 62,870	$ 26,022
Less: Income allocated to participating securities	0		0	(1,308)	(439)
Net income (loss) available to common shareholders	(5,565)		73,609	61,562	25,583
Weighted average common shares outstanding	168,110	144,440	189,254	145,146	122,591
Basic Earnings (Loss) per Common Share	$ (0.03)	$ 0.21	$ 0.39	$ 0.42	$ 0.21
Less: Income allocated to participating securities	0		0	(1,281)	(432)
Add: interest expense on Debentures, net of tax	0		0	69	457
Net income (loss) available to common shareholders	$ (5,565)		$ 73,609	$ 61,658	$ 26,047
Dilutive effect of stock options and restricted stock units awards	0		1,786	2,782	1,970
Dilutive effect of Debentures	0		0	456	2,451
Weighted average common shares outstanding assuming dilution	168,110	147,927	191,040	148,384	127,012
Earnings (Loss) per Common Share Assuming Dilution	$ (0.03)	$ 0.20	$ 0.39	$ 0.42	$ 0.21