Deferred Costs, Acquired Lease Intangibles and Goodwill - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Jun. 30, 2020
Deferred Costs [Line Items]
Amortization expense related to deferred leasing costs and acquired deferred leasing costs	$ 10,400	$ 5,400	$ 22,100	$ 17,700
Rental revenue related to the amortization of below-market leases, net of above-market leases	4,200	700	5,615	2,953
Goodwill	491,479		491,479		$ 491,479
Observatory
Deferred Costs [Line Items]
Fair value in excess of carrying value (less than) (as a percent)						15.00%
Observatory
Deferred Costs [Line Items]
Goodwill	227,500		227,500
Real estate
Deferred Costs [Line Items]
Goodwill	264,000		264,000
Lease agreements
Deferred Costs [Line Items]
Amortization expense related to acquired lease intangibles	5,000	$ 1,500	8,300	$ 5,900
Unsecured revolving credit facility | Revolving credit facility
Deferred Costs [Line Items]
Net deferred financing costs	$ 7,800		$ 7,800		$ 2,100