Business Combination - Schedule of Pro Forma Information for Business Combinations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Business Acquisition Pro Forma Information [Line Items]
Total revenues	$ 1,981,579	$ 1,898,083
Net loss attributable to common stockholders	$ (70,988)	$ (1,374,283)
Net loss per share attributable to common stockholders - basic	$ (0.15)	$ (3.24)
Net loss per share attributable to common stockholders - diluted	$ (0.15)	$ (3.24)