Deferred Costs, Acquired Lease Intangibles and Goodwill - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Deferred Costs [Line Items]
Amortization expense related to deferred leasing costs and acquired deferred leasing costs	$ 6,100	$ 6,400	$ 11,700	$ 12,300
Rental revenue related to the amortization of below-market leases, net of above-market leases	700	$ 1,400	1,371	$ 2,274
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%		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	1,600	$ 2,400	3,300	$ 4,400
Unsecured revolving credit facility | Revolving credit facility
Deferred Costs [Line Items]
Net deferred financing costs	$ 8,300		$ 8,300		$ 2,100