Investments in Unconsolidated Joint Ventures (Statements of Operations of the Joint Ventures) (Details) (USD $) In Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Total revenue	$ 436,451		$ 393,841		$ 854,326		$ 771,912
Interest	95,236		96,755		194,387		188,784
Depreciation and amortization	111,080		81,400		220,508		164,475
Total expenses	282,318		228,421		562,171		461,371
Net loss	(69,738)		(72,487)		(117,932)		(134,994)
Income (loss) from unconsolidated joint ventures	8,882		7,465		16,858		15,375
Unconsolidated Joint Ventures [Member]
Total revenue	144,987	[1]	151,129	[1]	290,632	[1]	302,091	[1]
Operating	42,272		42,833		85,114		84,537
Interest	57,007		59,249		114,768		117,585
Depreciation and amortization	48,243		57,391		98,880		114,215
Total expenses	147,522		159,473		298,762		316,337
Net loss	(2,535)		(8,344)		(8,130)		(14,246)
Company's share of net loss	(2,284)		(3,775)		(5,339)		(6,720)
Basis differential	1,759		2,516		3,515		4,793
Elimination of inter-entity interest on partner loan	9,407		8,724		18,682		17,302
Income (loss) from unconsolidated joint ventures	$ 8,882		$ 7,465		$ 16,858		$ 15,375

[1] Includes straight-line rent adjustments of $4.0 million and $5.6 million for the three months ended June 30, 2011 and 2010, respectively, and $8.1 million and $13.8 million for the six months ended June 30, 2011 and 2010, respectively. Includes net "above-" and "below-market" rent adjustments of $29.2 million and $30.4 million for the three months ended June 30, 2011 and 2010, respectively, and $58.7 million and $67.2 million for the six months ended June 30, 2011 and 2010, respectively.