Earnings Per Share ("EPS"): (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator
Income from continuing operations									$ 1,606,931	$ 159,023	$ 303,166
Income from discontinued operations									0	289,936	63,223
Net income attributable to noncontrolling interests									(107,889)	(28,869)	(28,963)
Net income attributable to the Company	1,429,221	35,914	16,088	17,819	144,878	38,123	218,997	18,092	1,499,042	420,090	337,426
Allocation of earnings to participating securities									(1,576)	(397)	(577)
Numerator for basic and diluted earnings per share—net income attributable to common stockholders - basic									1,497,466	419,693	336,849
Numerator for basic and diluted earnings per share—net income attributable to common stockholders - diluted									$ 1,497,466	$ 419,693	$ 336,849
Denominator
Denominator for basic earnings per share—weighted average number of common shares outstanding									143,144	139,598	134,067
Effect of dilutive securities
Stock warrants									0	0	63
Share and unit based compensation									147	82	18
Denominator for diluted earnings per share—weighted average number of common shares outstanding									143,291	139,680	134,148
Earnings per common share—basic: (in dollars per share)
Income from continuing operations									$ 10.46	$ 1.07	$ 2.07
Discontinued operations									$ 0.00	$ 1.94	$ 0.44
Net income attributable to common stockholders (in dollars per share)	$ 9.52	$ 0.25	$ 0.11	$ 0.13	$ 1.03	$ 0.27	$ 1.57	$ 0.13	$ 10.46	$ 3.01	$ 2.51
Earnings per common share—diluted: (in dollars per share)
Income from continuing operations									$ 10.45	$ 1.06	$ 2.07
Discontinued operations									$ 0.00	$ 1.94	$ 0.44
Net income attributable to common stockholders (in dollars per share)	$ 9.51	$ 0.25	$ 0.11	$ 0.13	$ 1.03	$ 0.27	$ 1.57	$ 0.13	$ 10.45	$ 3.00	$ 2.51