Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 86,477	$ 76,907	$ 67,925
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization, including amortization of debt issuance costs	36,374	33,671	31,919
Straight-lining of rental income	2,347	(1,418)	(2,538)
Stock-based compensation expense	450	600	394
Reversal of income tax liability	0	0	(420)
Change in operating assets and liabilities:
Tenant and other receivables, net	958	(1,801)	712
Other assets	(9,894)	(4,777)	(4,334)
Amounts due to Vornado	(1,913)	2,228	(42,779)
Accounts payable and accrued expenses	16,049	822	(1,373)
Other liabilities	(28)	(31)	(19)
Net cash provided by operating activities	130,820	106,201	49,487
CASH FLOWS FROM INVESTING ACTIVITIES
Construction in progress and real estate additions	(15,506)	(50,121)	(61,964)
Proceeds from maturing (purchases of) short-term investments	0	24,998	(24,998)
Restricted cash	(445)	(705)	5,442
Net cash used in investing activities	(15,951)	(25,828)	(81,520)
CASH FLOWS FROM FINANCING ACTIVITIES
Debt repayments	(3,440)	(323,193)	(317,179)
Proceeds from borrowing	0	350,000	300,000
Dividends paid	(81,822)	(71,571)	(66,436)
Debt issuance costs	(30)	(4,075)	(4,255)
Net cash used in financing activities	(85,292)	(48,839)	(87,870)
Net increase (decrease) in cash and cash equivalents	29,577	31,534	(119,903)
Cash and cash equivalents at beginning of year	259,349	227,815	347,718
Cash and cash equivalents at end of year	288,926	259,349	227,815
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash payments for interest, excluding capitalized interest of $1,486 in 2015	19,517	22,354	30,656
NON-CASH TRANSACTIONS
Liability for real estate additions, including $54 and $5,795 due to Vornado in 2016 and 2015, respectively	322	10,139	13,529
Write-off of fully amortized and/or depreciated assets	$ 1,691	$ 20,786	$ 10,626