CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities:
Net (loss) income	$ (29,603)	$ 18,993	$ 107,176
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	248,347	258,225	266,037
Straight-lining of rental revenue	(43,679)	(59,061)	(54,453)
Real estate impairment loss	42,000	46,000
Amortization of stock-based compensation expense	22,860	19,646	15,922
Amortization of deferred financing costs	19,323	11,023	11,188
Amortization of above and below-market leases, net	(10,991)	(16,059)	(19,523)
Loss (income) from unconsolidated joint ventures	4,706	(3,468)	(20,185)
Distributions of earnings from unconsolidated joint ventures	4,067	6,207	5,700
Realized and unrealized (gains) losses on marketable securities	(3,027)	1,604	(4,664)
Repayment of accrued interest on preferred equity investment	2,339
Distributions of earnings from unconsolidated real estate funds	1,553	330	342
Gain on sale of real estate	(1,140)	(36,845)	(133,989)
Loss on early extinguishment of debt	731		7,877
Loss from unconsolidated real estate funds	343	269	6,143
Other non-cash adjustments	(961)	288	(470)
Valuation allowance on preferred equity investment			19,588
Unrealized gain on interest rate swaps			(1,802)
Changes in operating assets and liabilities:
Accounts and other receivables	845	(2,994)	(1,000)
Deferred charges	(23,029)	(31,861)	(33,295)
Other assets	57,318	(57,216)	10,243
Accounts payable and accrued expenses	(8,949)	4,200	6,305
Other liabilities	2,388	(2,758)	2,971
Net cash provided by operating activities	285,441	156,523	190,111
Cash Flows from Investing Activities:
Investment in and contributions of capital to unconsolidated joint ventures	(368,852)	(29,883)	(28,791)
Due from affiliates	(217,918)
Repayment of amounts due from affiliates	181,000
Proceeds from sale of real estate	150,307	349,013	540,333
Additions to real estate	(103,916)	(137,915)	(86,434)
Redemption of preferred equity investment	33,750
Sales of marketable securities	19,282	24,794	27,261
Purchases of marketable securities	(15,232)	(20,019)	(29,248)
Contributions of capital to unconsolidated real estate funds	(3,937)	(3,779)	(790)
Distributions of capital from unconsolidated real estate funds	2,076	79	14,584
Escrow deposits and loans receivable for Residential Development Fund		(15,680)
Real estate acquisition deposits		(10,000)
Acquisitions of real estate			(161,184)
Distributions of capital from unconsolidated joint ventures			20,000
Net cash (used in) provided by investing activities	(323,440)	156,610	295,731
Cash Flows from Financing Activities:
Proceeds from notes and mortgages payable	1,259,843	16,700	991,556
Repayments of notes and mortgages payable	(1,050,000)		(1,044,821)
Borrowings under revolving credit facility	231,918		60,000
Repayment of borrowings under revolving credit facility	(195,000)		(290,000)
Repurchases of common shares	(97,137)	(102,863)
Dividends paid to common stockholders	(93,038)	(94,991)	(89,276)
Distributions to noncontrolling interests	(45,239)	(18,184)	(119,251)
Contributions from noncontrolling interests	14,989	45,116	100,777
Debt issuance costs and other	(10,131)	(6,564)	(7,490)
Distributions paid to common unitholders	(10,073)	(10,064)	(11,504)
Acquisition of noncontrolling interest in consolidated real estate fund	(1,000)
Loss on early extinguishment of debt	(731)		(7,877)
Repurchase of shares related to stock compensation agreements and related tax withholdings	(324)
Repayment of loans to affiliates		(27,299)
Transfer tax refund in connection with the acquisition of noncontrolling interests			9,555
Settlement of interest rate swap liabilities			(19,425)
Net cash provided by (used in) financing activities	4,077	(198,149)	(427,756)
Net (decrease) increase in cash and cash equivalents and restricted cash	(33,922)	114,984	58,086
Cash and cash equivalents and restricted cash at beginning of period	365,409	250,425	192,339
Cash and cash equivalents and restricted cash at end of period	331,487	365,409	250,425
Reconciliation of Cash and Cash Equivalents and Restricted Cash:
Cash and cash equivalents at beginning of period	339,653	219,381	162,965
Restricted cash at beginning of period	25,756	31,044	29,374
Cash and cash equivalents and restricted cash at beginning of period	365,409	250,425	192,339
Cash and cash equivalents at end of period	306,215	339,653	219,381
Restricted cash at end of period	25,272	25,756	31,044
Cash and cash equivalents and restricted cash at end of period	331,487	365,409	250,425
Supplemental Disclosure of Cash Flows Information:
Cash payments for interest	139,130	136,452	132,361
Cash payments for income taxes, net of refunds	2,474	4,049	5,048
Non-Cash Transactions:
Change in value of interest rate swaps	28,069	(7,273)	(10,618)
Dividends and distributions declared but not yet paid	25,255	25,902	25,211
Common shares issued upon redemption of commons units	24,030	3,461	172,728
Additions to real estate included in accounts payable and accrued expenses	21,566	19,872	10,413
Note payable issued in connection with the acquisition of noncontrolling interest in consolidated real estate fund	8,771
Write-off of fully amortized and/or depreciated assets	$ 8,727	4,158	9,684
Basis adjustment to investment in unconsolidated joint ventures upon adoption of ASU 2017-05		$ 7,086
Consolidation of real estate and real estate fund investments			102,512
Assumption of notes and mortgages payable			$ 228,000