Equity (Details 5) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation Of Accumulated Comprehensive Income
Balance - beginning of period	$ (4,649)	$ (8,507)	$ (3,463)
Other comprehensive (loss) income before reclassifications	19,042	3,408	(5,927)
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	2,813	2,132	532
Net current period other comprehensive (loss) income	21,855	5,540	(5,395)
Net current period other comprehensive income attributable to noncontrolling interests and redeemable noncontrolling interests	(1,870)	(1,682)	351
Balance - end of period	15,336	(4,649)	(8,507)
Interest expense
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	1,745	1,539	344
Other income and (expenses)
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	537	239
Net income from equity investments in real estate and the Managed REITs
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	531	354	188
Realized and Unrealized Gains and (Losses) on Derivative Instruments
Reconciliation Of Accumulated Comprehensive Income
Balance - beginning of period	(7,508)	(5,246)	(1,658)
Other comprehensive (loss) income before reclassifications	(2,793)	(4,394)	(4,120)
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	2,813	2,132	532
Net current period other comprehensive (loss) income	20	(2,262)	(3,588)
Net current period other comprehensive income attributable to noncontrolling interests and redeemable noncontrolling interests	0	0	0
Balance - end of period	(7,488)	(7,508)	(5,246)
Realized and Unrealized Gains and (Losses) on Derivative Instruments | Interest expense
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	1,745	1,539	344
Realized and Unrealized Gains and (Losses) on Derivative Instruments | Other income and (expenses)
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	537	239
Realized and Unrealized Gains and (Losses) on Derivative Instruments | Net income from equity investments in real estate and the Managed REITs
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	531	354	188
Foreign Currency Translation Adjustments
Reconciliation Of Accumulated Comprehensive Income
Balance - beginning of period	2,828	(3,299)	(1,854)
Other comprehensive (loss) income before reclassifications	21,835	7,809	(1,796)
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	0	0	0
Net current period other comprehensive (loss) income	21,835	7,809	(1,796)
Net current period other comprehensive income attributable to noncontrolling interests and redeemable noncontrolling interests	(1,870)	(1,682)	351
Balance - end of period	22,793	2,828	(3,299)
Foreign Currency Translation Adjustments | Interest expense
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	0	0	0
Foreign Currency Translation Adjustments | Other income and (expenses)
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	0	0
Foreign Currency Translation Adjustments | Net income from equity investments in real estate and the Managed REITs
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	0	0	0
Unrealized Appreciation (Depreciation) on Marketable Securities
Reconciliation Of Accumulated Comprehensive Income
Balance - beginning of period	31	38	49
Other comprehensive (loss) income before reclassifications	0	(7)	(11)
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	0	0	0
Net current period other comprehensive (loss) income	0	(7)	(11)
Net current period other comprehensive income attributable to noncontrolling interests and redeemable noncontrolling interests	0	0	0
Balance - end of period	31	31	38
Unrealized Appreciation (Depreciation) on Marketable Securities | Interest expense
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	0	0	0
Unrealized Appreciation (Depreciation) on Marketable Securities | Other income and (expenses)
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	0	0
Unrealized Appreciation (Depreciation) on Marketable Securities | Net income from equity investments in real estate and the Managed REITs
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	$ 0	$ 0	$ 0