Summary of Significant Accounting Policies (Earnings Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2010		Sep. 30, 2010		Jun. 30, 2010		Mar. 31, 2010		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Computation of earnings per share
Net (loss) earnings from continuing operations																	$ (228,063)		$ 82,524		$ 47,224
Net earnings from discontinued operations																	0		0		6,806
Basic (loss) earnings per share from continuing operations (in dollars per share)																	$ (4.21)		$ 1.54		$ 1.03
Basic earnings per share from discontinued operations (in dollars per share)																	$ 0.00		$ 0.00		$ 0.15
Basic (loss) earnings per share (in dollars per share)	$ (7.62)	[1]	$ 2.45	[1]	$ 1.93	[1]	$ (0.98)	[1]	$ (0.40)	[1]	$ (0.06)	[1]	$ 1.65	[1]	$ 0.34	[1]	$ (4.21)	[1]	$ 1.54	[1]	$ 1.18
Dilutive (loss) earnings per share from continuing operations (in dollars per share)																	$ (4.21)		$ 1.52		$ 1.02
Dilutive earnings per share from discontinued operations (in dollars per share)																	$ 0.00		$ 0.00		$ 0.15
Dilutive (loss) earings per share (in dollars per share)	$ (7.62)	[1]	$ 2.42	[1]	$ 1.90	[1]	$ (0.98)	[1]	$ (0.40)	[1]	$ (0.06)	[1]	$ 1.64	[1]	$ 0.34	[1]	$ (4.21)	[1]	$ 1.52	[1]	$ 1.17
Basic weighted average shares (in shares)																	54,133,000		52,969,000		44,625,000
Add: Dilutive effects of stock options (in shares)																	0		460,000		221,000
Diluted weighted average shares (in shares)																	54,133,000		53,429,000		44,846,000
Options not included in the diluted earnings (loss) per share calculation (in shares)																	1,500,000		700,000		1,600,000
Continuing Operations
Computation of earnings per share
Less: earnings allocable to participating securities																	0		1,199		1,134
Net earnings from available for common shareholders																	(228,063)		81,325		46,090
Discontinued Operations
Computation of earnings per share
Less: earnings allocable to participating securities																	0		0		174
Net earnings from available for common shareholders																	$ 0		$ 0		$ 6,632

[1] The sum of the individual quarterly net (loss) earnings per common share amounts may not agree with year-to-date net (loss) earnings per common share as each quarterly computation is based on the weighted-average number of common shares outstanding during that period. Potentially dilutive securities were included in the computation of diluted net (loss) earnings per common share for each quarter in which the Company reported net