Variable Interest Entities - Consolidated Assets and Liabilities of VIEs (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
ASSETS
Buildings and improvements	$ 11,220,557	$ 10,877,248
Development costs and construction in progress	605,165	537,643
Land	1,717,259	1,637,506
Accumulated depreciation and amortization	(2,915,798)	(2,842,947)
Net real estate	10,627,183	10,209,450
Investments in and advances to unconsolidated joint ventures	531,966	540,088
Accounts receivable, net	48,555	48,171
Cash and cash equivalents	120,117	110,790	$ 86,021
Restricted cash	26,535	29,056	$ 31,947
Intangible assets, net	275,565	305,079
Right-of-use asset, net	165,748	0
Other assets, net	643,456	591,017
Total assets	12,899,501	12,718,553
LIABILITIES AND EQUITY
Mortgage debt	137,525	138,470
Intangible liabilities, net	49,488	54,663
Lease liability	152,837	0
Accounts payable and accrued liabilities	132	1,125
Deferred revenue	181,467	190,683
Total liabilities	6,500,436	6,205,962
VIEs
ASSETS
Buildings and improvements	2,001,875	1,949,582
Development costs and construction in progress	43,481	39,584
Land	196,484	151,746
Accumulated depreciation and amortization	(424,325)	(398,143)
Net real estate	1,817,515	1,742,769
Investments in and advances to unconsolidated joint ventures	1,534	1,550
Accounts receivable, net	6,811	7,904
Cash and cash equivalents	32,831	23,772
Restricted cash	3,386	3,399
Intangible assets, net	96,197	111,333
Right-of-use asset, net	93,796	0
Other assets, net	44,312	43,149
Total assets	2,096,382	1,933,876
LIABILITIES AND EQUITY
Mortgage debt	44,500	44,598
Intangible liabilities, net	17,014	19,128
Lease liability	90,043	0
Accounts payable and accrued liabilities	56,542	66,736
Deferred revenue	23,536	24,215
Total liabilities	$ 231,635	$ 154,677