Deferred Costs, Acquired Lease Intangibles and Goodwill - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred Costs [Line Items]
Amortization of deferred leasing and acquired deferred leasing costs	$ 24,200	$ 25,400	$ 21,900
Amortization of acquired above and below-market leases, net	8,795	19,353	14,095
Goodwill	491,479	491,479
Empire State Building observatory operations [Member]
Deferred Costs [Line Items]
Goodwill				$ 227,500
Empire State Building [Member]
Deferred Costs [Line Items]
Goodwill				250,800
501 Seventh Avenue [Member]
Deferred Costs [Line Items]
Goodwill				$ 13,200
Lease agreements [Member]
Deferred Costs [Line Items]
Amortization expense related to acquired lease intangibles	$ 24,600	$ 37,700	$ 33,700
Ground lease [Member]
Deferred Costs [Line Items]
Weighted-average amortization period	25 years 6 months
In-place leases and deferred leasing costs [Member]
Deferred Costs [Line Items]
Weighted-average amortization period	4 years 10 months 24 days
Above-market leases [Member]
Deferred Costs [Line Items]
Weighted-average amortization period	3 years 10 months 24 days
Below-market Lease [Member]
Deferred Costs [Line Items]
Weighted-average amortization period	4 years 5 months
Unsecured revolving credit facility [Member] | Revolving credit facility [Member]
Deferred Costs [Line Items]
Net deferred financing costs	$ 4,500