Unconsolidated Affiliates and Cost Method Investments (Summarized Financial Information) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Equity Method Investment, Summarized Financial Information, Balance Sheet [Abstract]
Investment in real estate assets	$ 2,167,227	$ 2,143,187
Accumulated depreciation	(555,174)	(492,864)
Investment in real estate, net	1,612,053	1,650,323
Developments in progress	103,161	21,809
Net investment in real estate assets	1,715,214	1,672,132
Other assets	168,799	175,540
Total assets	1,884,013	1,847,672
Mortgage and other indebtedness	1,468,422	1,456,622
Other liabilities	48,203	48,538
Total liabilities	1,516,625	1,505,160
The Company	213,664	196,694
Other investors	153,724	145,818
Total owners' equity	367,388	342,512
Total liabilities and owners’ equity	1,884,013	1,847,672
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Revenues	243,215	251,628	177,222
Depreciation and amortization	(76,323)	(82,534)	(58,538)
Other operating expenses	(72,166)	(76,567)	(53,417)
Income from operations	94,726	92,527	65,267
Interest income	1,359	1,365	1,420
Interest expense	(76,934)	(84,421)	(59,972)
Gain on sales of real estate assets	102	2,063	1,744
Net income	$ 19,253	$ 11,534	$ 8,459