Basis of Presentation and Summary of Significant Accounting Policies (Details 4) (Fair Value, Inputs, Level 3 [Member], USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Fair Value, Inputs, Level 3 [Member]
Fair value of assets and liabilities measured on a nonrecurring basis
Fair value measurement, impairment losses on real estate	$ 49,114	$ 29,050
Total gain (loss), impairments losses on real estate	(7,390)	(6,883)
Fair value measurement, Real estate newly consolidated	0	117,083
Total gain (loss), Real estate newly consolidated		236
Fair value measurement, Property debt newly consolidated	$ 0	$ 83,890