Variable Interest Entities - Consolidated Variable Interest Entities (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
ASSETS
Development costs and construction in progress	$ 430,007	$ 400,619
Land	1,772,174	1,881,487
Accumulated depreciation and amortization	(2,577,248)	(2,648,930)
Net real estate	10,633,704	11,325,830
Investments in and advances to unconsolidated joint ventures	827,202	571,491
Accounts receivable	31,500	45,116
Cash and cash equivalents	764,114	94,730	$ 91,087
Restricted cash	60,806	42,260
Intangible assets, net	432,109	479,805
Other assets, net	605,407	711,624
Total assets	14,855,868	15,759,265
LIABILITIES AND EQUITY
Mortgage debt	147,329	623,792
Intangible liabilities, net	54,472	58,145
Liabilities of assets held for sale, net		3,776
Deferred Revenue	141,561	149,181
Total liabilities	8,682,393	9,817,957
VIEs
ASSETS
Buildings and improvements	2,787,845	3,522,310
Development costs and construction in progress	23,837	31,953
Land	214,963	327,241
Accumulated depreciation and amortization	(535,012)	(676,276)
Net real estate	2,491,633	3,205,228
Investments in and advances to unconsolidated joint ventures	3,108	3,641
Accounts receivable	9,609	19,996
Cash and cash equivalents	37,005	35,844
Restricted cash	42,009	22,624
Intangible assets, net	139,281	169,027
Other assets, net	55,049	69,562
Total assets	2,777,694	3,525,922
LIABILITIES AND EQUITY
Mortgage debt	45,245	520,870
Intangible liabilities, net	8,734	8,994
Liabilities of assets held for sale, net	92,640	120,719
Deferred Revenue	16,077	23,456
Total liabilities	$ 162,696	$ 674,039