Segment Reporting (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information Profit Loss
Revenues	$ 139,008	$ 132,592	$ 112,221	$ 106,030	$ 160,841	$ 65,284	$ 62,405	$ 63,831	$ 489,851	$ 352,361	$ 309,711
Operating expenses	(105,076)	(91,625)	(80,811)	(75,194)	(108,938)	(82,133)	(55,422)	(52,998)	(352,706)	(299,491)	(186,908)
Interest expense									(103,728)	(46,448)	(18,210)
Other, net									52,472	87,921	85,632
Provision for income taxes									(1,252)	(6,772)	(37,214)
Income from continuing operations before income taxes									84,637	87,571	153,011
Real Estate Ownership
Segment Reporting Information Profit Loss
Revenues									315,965	129,181	67,064
Operating expenses									(178,962)	(92,441)	(29,336)
Interest expense									(103,728)	(46,448)	(18,210)
Other, net									51,704	84,043	82,937
Provision for income taxes									(4,703)	(4,001)	(2,243)
Income from continuing operations before income taxes									80,276	70,334	100,212
Investment Management
Segment Reporting Information Profit Loss
Revenues									173,886	223,180	242,647
Operating expenses									(173,744)	(207,050)	(157,572)
Other, net									768	3,878	2,695
Provision for income taxes									3,451	(2,771)	(34,971)
Income from continuing operations before income taxes									$ 4,361	$ 17,237	$ 52,799