Computation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule Of Computation Of Basic And Diluted Earnings Per Common Share [Line Items]
Loss from continuing operations, net of non-controlling interests in subsidiaries									$ (363,238)	$ (1,325,620)	$ (142,524)
Loss on discontinued operations									0	0	(8,405)
Net loss	$ (371,502)	$ 35,769	$ (87,689)	$ 60,184	$ (471,518)	$ (848,735)	$ (3,333)	$ (2,034)	$ (363,238)	$ (1,325,620)	$ (150,929)
Weighted average shares of common stock outstanding (used to calculate basic EPS)									76,649	72,172	70,058
Net effect of dilutive employee stock options based on the treasury stock method									411	136	270
Weighted average shares of common stock outstanding (used to calculate diluted EPS)									77,060	72,308	70,328
Net income / (loss) per common share-basic:
Continuing operations									$ (4.74)	$ (18.37)	$ (2.03)
Discontinued operations									$ 0.00	$ 0.00	$ (0.12)
Net income / (loss) from operations per share of common stock, basic									$ (4.74)	$ (18.37)	$ (2.15)
Net income / (loss) per common share-diluted:
Continuing operations									$ (4.74)	$ (18.37)	$ (2.03)
Discontinued operations									$ 0.00	$ 0.00	$ (0.12)
Net income / (loss) from operations per share of common stock, diluted									$ (4.74)	$ (18.37)	$ (2.15)