Disclosure About Fair Value of Financial Instruments - Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Assets [Abstract]
Mortgages and notes receivable, at fair value	$ 17,488	[1]	$ 18,990	[1]
Marketable securities of non-qualified deferred compensation plan (in prepaid expenses and other assets)	3,219		3,149
Tax increment financing bond (in prepaid expenses and other assets)	15,075		14,788
Impaired real estate assets and for-sale residential condominiums			12,767
Total Assets	35,782		49,694
Noncontrolling Interests in the Operating Partnership	124,201		110,655
Liabilities[Abstract]
Mortgages and notes payable, at fair value	2,000,039	[1]	1,992,937	[1]
Interest rate swaps (in accounts payable, accrued expenses and other liabilities)	1,098		2,202
Non-qualified deferred compensation obligation (in accounts payable, accrued expenses and other liabilities)	3,219		3,149
Financing obligations, at fair value	20,076	[1]	18,866	[1]
Total Liabilities	2,024,432		2,017,154
Level 1 [Member]
Assets [Abstract]
Mortgages and notes receivable, at fair value	0		0
Marketable securities of non-qualified deferred compensation plan (in prepaid expenses and other assets)	3,219		3,149
Tax increment financing bond (in prepaid expenses and other assets)	0		0
Impaired real estate assets and for-sale residential condominiums			0
Total Assets	3,219		3,149
Noncontrolling Interests in the Operating Partnership	124,201		110,655
Liabilities[Abstract]
Mortgages and notes payable, at fair value	0		0
Interest rate swaps (in accounts payable, accrued expenses and other liabilities)	0		0
Non-qualified deferred compensation obligation (in accounts payable, accrued expenses and other liabilities)	3,219		3,149
Financing obligations, at fair value	0		0
Total Liabilities	3,219		3,149
Level 2 [Member]
Assets [Abstract]
Mortgages and notes receivable, at fair value	17,488		18,990
Marketable securities of non-qualified deferred compensation plan (in prepaid expenses and other assets)	0		0
Tax increment financing bond (in prepaid expenses and other assets)	0		0
Impaired real estate assets and for-sale residential condominiums			0
Total Assets	17,488		18,990
Noncontrolling Interests in the Operating Partnership			0
Liabilities[Abstract]
Mortgages and notes payable, at fair value	2,000,039		1,992,937
Interest rate swaps (in accounts payable, accrued expenses and other liabilities)	1,098		2,202
Non-qualified deferred compensation obligation (in accounts payable, accrued expenses and other liabilities)	0		0
Financing obligations, at fair value	0		0
Total Liabilities	2,001,137		1,995,139
Level 3 [Member]
Assets [Abstract]
Mortgages and notes receivable, at fair value	0		0
Marketable securities of non-qualified deferred compensation plan (in prepaid expenses and other assets)	0		0
Tax increment financing bond (in prepaid expenses and other assets)	15,075		14,788
Impaired real estate assets and for-sale residential condominiums			12,767
Total Assets	15,075		27,555
Noncontrolling Interests in the Operating Partnership			0
Liabilities[Abstract]
Mortgages and notes payable, at fair value	0		0
Interest rate swaps (in accounts payable, accrued expenses and other liabilities)	0		0
Non-qualified deferred compensation obligation (in accounts payable, accrued expenses and other liabilities)	0		0
Financing obligations, at fair value	20,076		18,866
Total Liabilities	$ 20,076		$ 18,866

[1] Amounts carried at historical cost on our Consolidated Balance Sheets at March 31, 2012 and December 31, 2011, respectively.