Stock-Based Compensation and Equity (Details 5) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reconciliation Of Accumulated Comprehensive Income
Balance - beginning of period	$ 14,215	$ (2,984)	$ 15,336	$ (4,649)
Other comprehensive (loss) income before reclassifications	(39,383)	12,964	(43,444)	12,290
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	426	698	2,891	1,969
Net current period other comprehensive (loss) income	(38,957)	13,662	(40,553)	14,259
Net current period other comprehensive (income) loss attributable to noncontrolling interests and redeemable noncontrolling interest	3,471	(2,052)	3,946	(984)
Balance - end of period	(21,271)	8,626	(21,271)	8,626
Interest expense
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	661	436	2,024	1,311
Other income and (expenses)
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	(337)	206	487	182
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)	102	56	380	476
Gains and Losses on Derivative Instruments
Reconciliation Of Accumulated Comprehensive Income
Balance - beginning of period	(12,052)	(2,253)	(7,488)	(7,508)
Other comprehensive (loss) income before reclassifications	15,725	(4,711)	8,696	(727)
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	426	698	2,891	1,969
Net current period other comprehensive (loss) income	16,151	(4,013)	11,587	1,242
Net current period other comprehensive (income) loss attributable to noncontrolling interests and redeemable noncontrolling interest	0	0	0	0
Balance - end of period	4,099	(6,266)	4,099	(6,266)
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)	661	436	2,024	1,311
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)	(337)	206	487	182
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)	102	56	380	476
Foreign Currency Translation Adjustments
Reconciliation Of Accumulated Comprehensive Income
Balance - beginning of period	26,224	(762)	22,793	2,828
Other comprehensive (loss) income before reclassifications	(55,096)	17,675	(52,140)	13,017
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	0	0	0	0
Net current period other comprehensive (loss) income	(55,096)	17,675	(52,140)	13,017
Net current period other comprehensive (income) loss attributable to noncontrolling interests and redeemable noncontrolling interest	3,471	(2,052)	3,946	(984)
Balance - end of period	(25,401)	14,861	(25,401)	14,861
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	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	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	0
Gains and Losses on Marketable Securities
Reconciliation Of Accumulated Comprehensive Income
Balance - beginning of period	43	31	31	31
Other comprehensive (loss) income before reclassifications	(12)	0	0	0
Amounts reclassified from accumulated other comprehensive income (loss) to:
Amount reclassified from accumulated other comprehensive income (loss)	0	0	0	0
Net current period other comprehensive (loss) income	(12)	0	0	0
Net current period other comprehensive (income) loss attributable to noncontrolling interests and redeemable noncontrolling interest	0	0	0	0
Balance - end of period	31	31	31	31
Gains and Losses 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	0
Gains and Losses 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	0	0
Gains and Losses 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	$ 0