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Commitments and Contingencies - Additional Information (Details) - ft²
12 Months Ended
Dec. 31, 2017
Nov. 23, 2014
Other Commitments [Line Items]    
Area of office properties 12,500,000  
718 Fifth Avenue [Member]    
Other Commitments [Line Items]    
Put right notice period 12 months  
712 Fifth Avenue [Member]    
Other Commitments [Line Items]    
Equity method ownership percentage 50.00%  
Predecessor [Member] | 718 Fifth Avenue [Member]    
Other Commitments [Line Items]    
Percentage of tenancy-in-common interest in property   50.00%
Predecessor [Member] | 712 Fifth Avenue [Member]    
Other Commitments [Line Items]    
Equity method ownership percentage 50.00%  
Owned by Affiliate [Member] | Predecessor [Member] | 718 Fifth Avenue [Member] | Third Party Affiliate [Member]    
Other Commitments [Line Items]    
Equity method ownership percentage   25.00%
Owned by Affiliate [Member] | Parent Company [Member] | Put Right Exercised [Member] | 718 Fifth Avenue [Member]    
Other Commitments [Line Items]    
Pre IPO ownership percentage 25.00%  
Owned by Affiliate [Member] | Retail Type Space [Member] | Predecessor [Member] | 718 Fifth Avenue [Member]    
Other Commitments [Line Items]    
Area of office properties   19,050