Equity Investment in Real Estate and the REITs (Details 2) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Equity Method Investment Summarized Financial Information Income Statement [Abstract]
Income from equity investments in real estate and REITs	$ 12,465,000	$ 7,638,000	$ 18,681,000	$ 16,780,000
Other Equity Investment Information [Abstract]
Termination Revenue			31,200,000
Shares Received From REIT Arising From Merger			13,260,091
Additional Shares Purchased			13,750,000
Value Of Additional Shares Purchased			121,000,000
Payment For Special Interest			300,000
Equity Adjustment			28,300,000
Fair Value Of Shares Converted During Merger			118,000,000
Gain Recorded Resulting From Shares Exchanged In Merger	2,800,000		2,800,000
REITs [Member]
Equity Method Investment Summarized Financial Information [Abstract]
Equity Method Investment Summarized Financial Information Assets	9,239,065,000		9,239,065,000		8,533,899,000
Equity Method Investment Summarized Financial Information Liabilities	(5,008,673,000)		(5,008,673,000)		(4,632,709,000)
Equity Method Investment Summarized Financial Information Equity Or Capital	4,230,392,000		4,230,392,000		3,901,190,000
Equity Method Investment Summarized Financial Information Income Statement [Abstract]
Revenues	204,105,000	201,334,000	402,773,000	394,088,000
Expenses	(126,530,000)	(151,906,000)	(272,374,000)	(293,530,000)
Impairment charges	(29,831,000)	(886,000)	(39,839,000)	(12,980,000)
Net Income	47,744,000	48,542,000	90,560,000	87,578,000
Income from equity investments in real estate and REITs	6,800,000	2,800,000	8,600,000	5,100,000
Reduction in income from equity method investments	4,400,000	100,000	5,100,000	700,000
Real Estate [Member]
Equity Method Investment Summarized Financial Information [Abstract]
Equity Method Investment Summarized Financial Information Assets	1,106,283,000		1,106,283,000		1,151,859,000
Equity Method Investment Summarized Financial Information Liabilities	(766,170,000)		(766,170,000)		(818,238,000)
Equity Method Investment Summarized Financial Information Equity Or Capital	340,113,000		340,113,000		333,621,000
Equity Method Investment Summarized Financial Information Income Statement [Abstract]
Revenues	30,364,000	37,849,000	60,918,000	76,058,000
Expenses	(20,090,000)	(19,948,000)	(40,738,000)	(39,657,000)
Impairment charges	(40,000)	0	(8,602,000)	0
Net Income	10,234,000	17,901,000	11,578,000	36,401,000
Income from equity investments in real estate and REITs	$ 3,700,000	$ 6,300,000	$ 3,700,000	$ 9,900,000