Earnings Per Share ("EPS"): (Details) (USD $) In Thousands, except 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
Numerator
Income from continuing operations									$ 297,024	$ 243,946	$ 38,770
Income (loss) from discontinued operations									69,365	(74,871)	(10,350)
Net income attributable to noncontrolling interests									(28,963)	(12,209)	(3,230)
Net income attributable to the Company	174,247	43,893	133,354	(14,068)	163,107	12,941	(19,216)	34	337,426	156,866	25,190
Allocation of earnings to participating securities									(577)	(1,436)	(2,615)
Numerator for basic earnings per share-net income attributable to common stockholders									336,849	155,430	22,575
Numerator for diluted earnings per share-net income attributable to common stockholders									$ 336,849	$ 155,430	$ 22,575
Denominator
Denominator for basic earnings per share-weighted average number of common shares outstanding									134,067,000	131,628,000	120,346,000
Effect of dilutive securities
Stock warrants									63,000
Share and unit based compensation									18,000
Denominator for diluted earnings per share-weighted average number of common shares outstanding									134,148,000	131,628,000	120,346,000
Earnings per common share-basic:
Income from continuing operations (in dollars per share)									$ 2.03	$ 1.70	$ 0.27
Discontinued operations (in dollars per share)									$ 0.48	$ (0.52)	$ (0.08)
Net income attributable to common stockholders	$ 1.27	$ 0.33	$ 1.00	$ (0.11)	$ 1.23	$ 0.10	$ (0.15)		$ 2.51	$ 1.18	$ 0.19
Earnings per common share-diluted:
Income from continuing operations (in dollars per share)									$ 2.03	$ 1.70	$ 0.27
Discontinued operations (in dollars per share)									$ 0.48	$ (0.52)	$ (0.08)
Net income attributable to common stockholders	$ 1.27	$ 0.33	$ 1.00	$ (0.11)	$ 1.23	$ 0.10	$ (0.15)		$ 2.51	$ 1.18	$ 0.19