Consolidated Statements of Cash Flows (Unaudited) (USD $)	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash Flows - Operating Activities
Net income	$ 61,655,000	$ 42,899,000
Adjustments to net income:
Depreciation and amortization including intangible assets and deferred financing costs	67,658,000	15,054,000
Income from equity investments in real estate and the Managed REITs in excess of distributions received	(22,338,000)	(17,013,000)
Straight-line rent and amortization of rent-related intangibles	9,646,000	(2,016,000)
Amortization of dererred revenue	(4,718,000)	(4,718,000)
Gain on sale of real estate	(50,000)	(1,505,000)
Unrealized (gain) loss on foreign currency transactions and others	(3,220,000)	23,000
Realized loss on foreign currency transactions and other	181,000	535,000
Management income received in shares of Managed REITs	(20,215,000)	(14,005,000)
Impairment charges	4,950,000	6,728,000
Stock-based compensation expense	17,578,000	9,755,000
Deferred acquisition revenue received	12,402,000	13,322,000
Increase in structuring revenue receivable	(2,285,000)	(4,906,000)
Decrease in income taxes, net	(11,507,000)	(7,186,000)
Increase in prepaid taxes	(16,143,000)	(5,020,000)
Payment for withholding taxes upon delivery of equity-based awards and exercises of stock options	(10,435,000)	(4,396,000)
Net changes in other operating assets and liabilities	(11,706,000)	(15,746,000)
Net Cash Provided by Operating Activities	71,453,000	11,805,000
Cash Flows - Investing Activities
Distributions received from equity investments in real estate and the Managed REITs in excess of equity income	21,907,000	15,909,000
Capital contributions to equity investments	(1,455,000)	(180,000)
Purchases of real estate	(183,554,000)	0
Capital expenditures	(5,806,000)	(1,812,000)
Proceeds from sale of real estate and equity investments	48,902,000	25,195,000
Funds placed in escrow	(73,993,000)	(5,577,000)
Funds released from escrow	95,536,000	7,647,000
Other investing activities, net	(176,000)	198,000
Net Cash (Used in) Provided by Investing Activities	(98,639,000)	41,380,000
Cash Flows - Financing Activities
Distributions paid	(102,923,000)	(46,013,000)
Contributions from noncontrolling interests	2,830,000	1,480,000
Distributions paid to noncontrolling interests	(15,228,000)	(1,165,000)
Purchase of treasury stock from related party (Note 3), value	(40,000,000)	0
Scheduled payments of mortgage principal	(121,836,000)	(10,262,000)
Proceeds from mortgage financing	99,000,000	1,250,000
Proceeds from senior credit facility	230,000,000	15,000,000
Repayments of senior credit facility	(98,000,000)	(15,000,000)
Funds released from escrow	(463,000)	0
Payment of financing costs and mortgage deposits, net of deposits refunded	(305,000)	(123,000)
Proceeds from exercise of stock options and employee purchase under the employee share purchase plan	1,970,000	5,692,000
Windfall tax benefit associated with stock-based compensation awards	11,556,000	6,607,000
Net Cash Used in Financing Activities	(33,399,000)	(42,534,000)
Change in Cash and Cash Equivalents During the Period
Effect of exchange rate changes on cash	(554,000)	(148,000)
Net (decrease) increase in cash and cash equivalents	(61,139,000)	10,503,000
Cash and cash equivalents, beginning of period	123,904,000	29,297,000
Cash and cash equivalents, end of period	62,765,000	39,800,000
Supplemental noncash investing and financing activities
Reclassifcation To (From) Net Direct Financing Lease	5,600,000
Dividends Payable Current And Noncurrent	58,036,000	23,000,000
Schedule of Real Estate Assets [Line Items]
Real estate, net	2,450,868,000
Other Intangible Assets Net	12,256,000
Assets Held For Sale [Member]
Schedule of Real Estate Assets [Line Items]
Real estate, net	20,000,000
Other Intangible Assets Net	$ 1,300,000