Accounting Policies Accounting Policies (Details 3) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Investing Activities
Decrease in projects under construction and development	$ 351,905,000	$ 20,919,000
Decrease in completed rental properties	136,008,000	853,875,000
(Increase) decrease in restricted cash	(20,000)	4,326,000
Increase in notes and accounts receivable	(2,728,000)	0
Increase in investments in and advances to affiliates	(122,663,000)	(34,885,000)
Total effect on investing activities	362,502,000	844,235,000
Financing Activities
Increase in accounts payable, accrued expenses and other liabilities	10,683,000	0
Decrease in nonrecourse mortgage debt and notes payable	(342,960,000)	(868,342,000)
Decrease in convertible senior debt	0	(218,675,000)
Decrease in preferred stock	0	(5,489,000)
Increase in Class A common stock	225,000	4,681,000
Increase in additional paid-in capital	34,741,000	179,617,000
Increase in treasury stock	0	(12,868,000)
Increase in redeemable noncontrolling interest	28,390,000	9,939,000
(Decrease) increase in noncontrolling interest	(73,535,000)	32,059,000
Total effect on financing activities	$ (342,456,000)	$ (879,078,000)