Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Real Estate, net	$ 6,773,022,000	$ 6,502,072,000
Cash and equivalents	326,518,000	280,206,000
Restricted cash	266,530,000	347,534,000
Other assets	409,366,000	415,316,000
Development project held for sale	0	504,171,000
Mortgage debt and notes payable, nonrecourse	4,238,201,000	4,351,506,000
Accounts payable, accrued expenses and other liabilities	847,011,000	831,920,000
Mortgage debt, nonrecourse of development project held for sale	0	228,000,000
Preferred stock, without par value	$ 0	$ 0
Preferred stock, shares authorized	13,600,000	13,600,000
Preferred stock, shares issued	0	0
Variable interest entities
Real Estate, net	427,800,000	656,800,000
Cash and equivalents	20,600,000	18,800,000
Restricted cash	28,600,000	154,500,000
Other assets	19,600,000	55,500,000
Development project held for sale	0	504,200,000
Mortgage debt and notes payable, nonrecourse	250,700,000	323,700,000
Accounts payable, accrued expenses and other liabilities	42,600,000	89,000,000
Mortgage debt, nonrecourse of development project held for sale	$ 0	$ 200,000
Common Stock Class A
Common stock, par value per share	$ 0.333	$ 0.333
Common stock, shares authorized	371,000,000	371,000,000
Common stock, shares issued	180,859,262	178,498,770
Common stock, shares outstanding	179,763,952	177,556,917
Treasury stock, Class A Shares	1,095,310	941,853
Common Stock Class B
Common stock, par value per share	$ 0.333	$ 0.333
Common stock, shares authorized	56,000,000	56,000,000
Common stock, shares issued	19,208,517	20,173,558
Common stock, shares outstanding	19,208,517	20,173,558
Common stock, shares issuable	26,257,961	26,257,961