Acquisitions Narrative (Details) (USD $)	0 Months Ended	3 Months Ended	12 Months Ended	0 Months Ended	9 Months Ended	12 Months Ended
	Oct. 06, 2013 entity	Dec. 31, 2013	Dec. 31, 2014	Jul. 15, 2014	Oct. 06, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Number of entities acquired	4
Gain on consolidation of non-controlled entities		$ 322,563,000	$ 0
Goodwill		491,479,000	491,479,000
Ground Lease [Member]
Business Acquisition [Line Items]
Weighted average useful life			26 years 4 months 30 days
Leases and Deferred Leasing Costs [Member]
Business Acquisition [Line Items]
Weighted average useful life			4 years 10 months 30 days
Acquired above-market leases [Member]
Business Acquisition [Line Items]
Weighted average useful life			4 years 2 months 30 days
Below Market Lease [Member]
Business Acquisition [Line Items]
Weighted average useful life			4 years 4 months 30 days
Total Acquisitions [Member]
Business Acquisition [Line Items]
Consideration paid	1,171,841,000			733,600,000
Debt assumed	124,354,000			167,684,000
Gain on consolidation of non-controlled entities	214,300,000
Goodwill	491,479,000				491,479,000
112 West 34th Street [Member]
Business Acquisition [Line Items]
Consideration paid				423,600,000
Debt assumed				87,700,000
Payments to Acquire Businesses, Gross				106,900,000
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable				229,000,000
Share price				$ 16.65
Empire State Building Observatory Operations [Member]
Business Acquisition [Line Items]
Goodwill	227,500,000				227,500,000
Empire State Building, L.L.C. [Member]
Business Acquisition [Line Items]
Goodwill	250,800,000				250,800,000
1333 Broadway Associates [Member]
Business Acquisition [Line Items]
Gain on consolidation of non-controlled entities	41,000,000
1350 Broadway Associates [Member]
Business Acquisition [Line Items]
Gain on consolidation of non-controlled entities	32,100,000
Location 1400 Broadway [Member]
Business Acquisition [Line Items]
Consideration paid				310,000,000
Debt assumed				80,000,000
Payments to Acquire Businesses, Gross				79,700,000
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable				150,300,000
Share price				$ 16.65
Empire State Building Company L.L.C. and 501 Seventh Avenue Associates L.L.C. [Member] [Member]
Business Acquisition [Line Items]
Gain on consolidation of non-controlled entities	35,200,000
501 Seventh Avenue Associates [Member]
Business Acquisition [Line Items]
Goodwill	13,200,000				13,200,000
Predecessor [Member]
Business Acquisition [Line Items]
Gain on consolidation of non-controlled entities					0	0
Noncontrolling interest ownership interest fair value	302,700,000
Noncontrolling interest ownership interest cost	88,400,000				$ 88,400,000
Predecessor [Member] | Empire State Building Co. [Member]
Business Acquisition [Line Items]
Ownership percentage	23.75%				23.75%
Predecessor [Member] | 1333 Broadway Associates [Member]
Business Acquisition [Line Items]
Ownership percentage	50.00%				50.00%
Predecessor [Member] | 1350 Broadway Associates [Member]
Business Acquisition [Line Items]
Ownership percentage	50.00%				50.00%
Predecessor [Member] | 501 Seventh Avenue Associates [Member]
Business Acquisition [Line Items]
Ownership percentage	20.469%				20.469%
Common Class A [Member] | 112 West 34th Street [Member]
Business Acquisition [Line Items]
Number of shares issued				1,217,685
Common Class A [Member] | Location 1400 Broadway [Member]
Business Acquisition [Line Items]
Number of shares issued				1,338,488
Common Class B [Member] | 112 West 34th Street [Member]
Business Acquisition [Line Items]
Number of shares issued				77,945
Common Class B [Member] | Location 1400 Broadway [Member]
Business Acquisition [Line Items]
Number of shares issued				32,452
Series ES Operating Partnership Units [Member] | 112 West 34th Street [Member]
Business Acquisition [Line Items]
Number of shares issued				12,457,379
Series ES Operating Partnership Units [Member] | Location 1400 Broadway [Member]
Business Acquisition [Line Items]
Number of shares issued				7,658,516