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	$ 132,930	$ 41,939	$ 60,075
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization, including amortization of debt issuance costs	34,592	35,121	36,515
Straight-lining of rents	9,817	21,102	2,413
Write-off of tenant receivables	0	4,122	0
Stock-based compensation expense	450	600	394
Net gains on sale of real estate (including $2,348 from discontinued operations)	(72,298)	0	0
Change in fair value of marketable securities	(3,482)	8,599	8,757
Dividends received in stock	0	(214)	0
Change in operating assets and liabilities:
Tenant and other receivables, net	1,731	(6,146)	(2,017)
Other assets	3,099	(28,378)	21,553
Amounts due to Vornado	(211)	(402)	789
Accounts payable and accrued expenses	12,501	2,361	(1,800)
Other liabilities	(664)	(638)	(609)
Net cash provided by operating activities	118,465	78,066	126,070
CASH FLOWS FROM INVESTING ACTIVITIES
Construction in progress and real estate additions	(19,520)	(32,460)	(9,449)
Proceeds from sales of real estate	81,871	0	0
Return of short-term investment	3,600	0	0
Proceeds from sale of marketable securities	9,506	0	0
Net cash provided by (used in) investing activities	75,457	(32,460)	(9,449)
CASH FLOWS FROM FINANCING ACTIVITIES
Dividends paid	(92,220)	(92,168)	(92,124)
Debt issuance costs	(74)	(7,246)	(15)
Debt repayments	(68,000)	(50,000)	0
Proceeds from borrowings	0	239,708	0
Net cash (used in) provided by financing activities	(160,294)	90,294	(92,139)
Net increase in cash and cash equivalents and restricted cash	33,628	135,900	24,482
Cash and cash equivalents and restricted cash at beginning of year	449,877	313,977	289,495
Cash and cash equivalents and restricted cash at end of year	483,505	449,877	313,977
RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH
Cash and cash equivalents at beginning of year	428,710	298,063	283,056
Restricted cash at beginning of year	21,167	15,914	6,439
Cash and cash equivalents and restricted cash at beginning of year	449,877	313,977	289,495
Cash and cash equivalents at end of year	463,539	428,710	298,063
Restricted cash at end of year	19,966	21,167	15,914
Cash and cash equivalents and restricted cash at end of year	483,505	449,877	313,977
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash payments for interest	18,568	22,476	34,669
NON-CASH TRANSACTIONS
Liability for real estate additions, including $141, $489 and $18 for development fees due to Vornado in 2021, 2020 and 2019, respectively	1,445	4,955	3,191
Write-off of fully amortized and/or depreciated assets	5,628	876	0
Reclassification of prepaid real estate taxes to construction in progress for property in redevelopment	0	0	1,466
Lease liability arising from the recognition of right-of-use asset	$ 0	$ 0	$ 5,428