CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash Flows from Operating Activities:
Net income (loss)	$ 2,059	$ (19,196)	$ (29,603)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	232,487	235,890	248,347
Loss from unconsolidated joint ventures	24,896	18,619	4,706
Amortization of stock-based compensation expense	18,612	19,239	22,860
Amortization of deferred financing costs	9,127	9,277	19,323
Distributions of earnings from unconsolidated joint ventures	7,278	3,999	4,067
Amortization of above and below-market leases, net	(3,070)	(4,734)	(10,991)
Straight-lining of rental revenue	(2,495)	(28,216)	(43,679)
Realized and unrealized gains on marketable securities	(1,535)	(1,918)	(3,027)
(Income) loss from unconsolidated real estate funds	(782)	(272)	343
Distributions of earnings from unconsolidated real estate funds	676	616	1,553
Loss (gain) on sale of real estate related to discontinued operations		12,766	(1,140)
Real estate impairment loss related to discontinued operations			42,000
Receipt of accrued interest on preferred equity investment			2,339
Loss on early extinguishment of debt			731
Other non-cash adjustments	3,146	413	(961)
Changes in operating assets and liabilities:
Accounts and other receivables	1,920	1,729	845
Deferred charges	(18,438)	(10,761)	(23,029)
Other assets	(8,283)	(2,193)	57,318
Accounts payable and accrued expenses	16,246	(1,299)	(8,949)
Other liabilities	(37,538)	3,313	2,388
Net cash provided by operating activities	244,306	237,272	285,441
Cash Flows from Investing Activities:
Additions to real estate	(112,001)	(89,463)	(103,916)
Sales of marketable securities	40,228	22,188	19,282
Purchases of marketable securities	(21,562)	(15,809)	(15,232)
Investments in and contributions of capital to unconsolidated joint ventures	(11,750)	(60)	(368,852)
Distributions of capital from unconsolidated real estate funds	4,926		2,076
Contributions of capital to unconsolidated real estate funds	(3,324)	(2,945)	(3,937)
Proceeds from the sale of real estate related to discontinued operations		89,206	150,307
Repayment of amounts due from affiliates		36,918	181,000
Due from affiliates			(217,918)
Redemption of preferred equity investment			33,750
Net cash (used in) provided by investing activities	(103,483)	40,035	(323,440)
Cash Flows from Financing Activities:
Proceeds from notes and mortgages payable	888,566	9,791	1,259,843
Repayment of notes and mortgages payable	(850,000)		(1,050,000)
Dividends paid to common stockholders	(61,297)	(89,225)	(93,038)
Distributions paid to common unitholders	(6,182)	(8,837)	(10,073)
Distributions to noncontrolling interests	(30,539)	(12,717)	(45,239)
Contributions from noncontrolling interests	121	11,555	14,989
Debt issuance costs	(16,775)		(10,131)
Repurchase of shares related to stock compensation agreements and related tax withholdings	(235)	(332)	(324)
Purchase of interest rate caps	(140)
Repayment of borrowings under revolving credit facility		(200,000)	(195,000)
Borrowings under revolving credit facility		163,082	231,918
Repurchases of common shares		(120,000)	(97,137)
Proceeds from the sale of a 10.0% interest in 1633 Broadway		111,984
Repayment of note payable issued in connection with the acquisition of noncontrolling interest in consolidated real estate fund		(8,771)
Acquisition of noncontrolling interest in consolidated real estate fund			(1,000)
Loss on early extinguishment of debt			(731)
Net cash (used in) provided by financing activities	(76,481)	(143,470)	4,077
Net increase (decrease) in cash and cash equivalents and restricted cash	64,342	133,837	(33,922)
Cash and cash equivalents and restricted cash at beginning of period	465,324	331,487	365,409
Cash and cash equivalents and restricted cash at end of period	529,666	465,324	331,487
Reconciliation of Cash and Cash Equivalents and Restricted Cash:
Cash and cash equivalents at beginning of period	434,530	306,215	339,653
Restricted cash at beginning of period	30,794	25,272	25,756
Cash and cash equivalents and restricted cash at beginning of period	465,324	331,487	365,409
Cash and cash equivalents at end of period	524,900	434,530	306,215
Restricted cash at end of period	4,766	30,794	25,272
Cash and cash equivalents and restricted cash at end of period	529,666	465,324	331,487
Supplemental Disclosure of Cash Flow Information:
Cash payments for interest	132,476	135,607	139,130
Cash payments for income taxes, net of refunds	1,762	1,366	2,474
Non-Cash Transactions:
Write-off of fully amortized and/or depreciated assets	46,594	9,141	8,727
Dividends and distributions declared but not yet paid	16,895	16,796	25,255
Additions to real estate included in accounts payable and accrued expenses	12,177	8,640	21,566
Change in value of interest rate swaps and interest rate caps	6,857		28,069
Transfer of deposit to investment in unconsolidated joint ventures	6,230
Common shares issued upon redemption of common units	$ 961	$ 85,710	24,030
Note payable issued in connection with the acquisition of noncontrolling interest in consolidated real estate fund			$ 8,771