Summary of Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2020
Accounting Policies [Line Items]
Deferred revenue	$ 800,000	$ 2,700,000
Advertising and marketing expense	7,400,000	9,700,000	$ 8,900,000
Capitalized interest	$ 0	$ 1,400,000	$ 1,600,000
Number of reportable segments | segment	2
Observatory Reporting Unit
Accounting Policies [Line Items]
Fair value in excess of carrying value (less than) (as a percent)				5.00%
Building and Building Improvements
Accounting Policies [Line Items]
Useful life (in years)	39 years
Corporate Equipment | Minimum
Accounting Policies [Line Items]
Useful life (in years)	3 years
Corporate Equipment | Maximum
Accounting Policies [Line Items]
Useful life (in years)	7 years