Risk Management and Use of Derivative Financial Instruments (Narratives) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Foreign currency exchange rate	1.3768	1.3218
Footnote Details
Derivative fair value	$ (9,811,000)
Derivative Instrument Detail
Collateral received	0
Total credit exposure on derivatives	3,100,000
Total credit exposure on derivatives to a single counterparty	2,000,000
Derivatives, net liability position	25,100,000	23,000,000
Aggregate termination value for immediate settlement	27,100,000	25,100,000
Interest rate swap
Footnote Details
Derivative notional amount	210,218,000
Derivative fair value	(2,327,000)
Derivative Instrument Detail
Estimated amount reclassified from OCI to income, derivatives	8,000,000
Interest rate swap | Noncontrolling interest
Derivative Instrument Detail
Estimated amount reclassified from OCI to income, derivatives	400,000
Foreign currency contract
Derivative Instrument Detail
Estimated amount reclassified from OCI to income, derivatives	300,000
Interest rate cap
Derivatives, Fair Value [Line Items]
Gain attributable to noncontrolling interests	500,000	400,000	(100,000)
Footnote Details
Debt, interest rate at period end	2.80%
Cap rate	4.00%
Derivative notional amount	115,675,000
Derivative fair value	0
Interest rate cap | Noncontrolling interest
Footnote Details
Derivative notional amount	$ 52,100,000
Embedded derivatives
Derivatives, Fair Value [Line Items]
Foreign currency exchange rate	1.278