Condensed Consolidated Statements of Capital - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance		$ 1,982,863
Equity compensation		10,808
Distributions		(95,186)
Net income	$ 35,489	85,993
Unrealized gain (loss) on valuation of interest rate swap agreements	(1,279)	(14,252)
Ending balance	$ 1,970,226	$ 1,970,226
General Partner | Series PR operating partnership units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		155,841
Beginning balance		$ 1,154,136
Conversion of operating partnership units to ESRT Partner's Capital (in units)		3,558
Conversion of operating partnership units to ESRT Partner's Capital		$ 11,069
Equity compensation (in units)		28
Equity compensation		$ 476
Distributions		(49,843)
Net income		45,375
Unrealized gain (loss) on valuation of interest rate swap agreements		$ (7,582)
Ending balance (in units)	159,427	159,427
Ending balance	$ 1,153,631	$ 1,153,631
Limited Partner | Series PR operating partnership units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		93,075
Beginning balance		$ 793,360
Conversion of operating partnership units to ESRT Partner's Capital (in units)		(1,167)
Conversion of operating partnership units to ESRT Partner's Capital		$ (9,890)
Equity compensation (in units)		1,296
Equity compensation		$ 10,332
Distributions		(29,329)
Net income		25,758
Unrealized gain (loss) on valuation of interest rate swap agreements		$ (4,304)
Ending balance (in units)	93,204	93,204
Ending balance	$ 785,927	$ 785,927
Limited Partner | Series ES operating partnership units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		35,728
Beginning balance		$ 20,091
Conversion of operating partnership units to ESRT Partner's Capital (in units)		(1,556)
Conversion of operating partnership units to ESRT Partner's Capital		$ (803)
Distributions		(10,929)
Net income		10,064
Unrealized gain (loss) on valuation of interest rate swap agreements		$ (1,682)
Ending balance (in units)	34,172	34,172
Ending balance	$ 16,741	$ 16,741
Limited Partner | Series 60 operating partnership units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		9,701
Beginning balance		$ 4,880
Conversion of operating partnership units to ESRT Partner's Capital (in units)		(564)
Conversion of operating partnership units to ESRT Partner's Capital		$ (252)
Distributions		(2,944)
Net income		2,729
Unrealized gain (loss) on valuation of interest rate swap agreements		$ (456)
Ending balance (in units)	9,137	9,137
Ending balance	$ 3,957	$ 3,957
Limited Partner | Series 250 operating partnership units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		4,747
Beginning balance		$ 2,392
Conversion of operating partnership units to ESRT Partner's Capital (in units)		(271)
Conversion of operating partnership units to ESRT Partner's Capital		$ (124)
Distributions		(1,439)
Net income		1,365
Unrealized gain (loss) on valuation of interest rate swap agreements		$ (228)
Ending balance (in units)	4,476	4,476
Ending balance	$ 1,966	$ 1,966
Private Perpetual Preferred Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in units)		1,560
Beginning balance		$ 8,004
Distributions		(702)
Net income		$ 702
Ending balance (in units)	1,560	1,560
Ending balance	$ 8,004	$ 8,004