Income Taxes - Schedule of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Deferred revenue on unredeemed observatory admission ticket sales	$ 256	$ 916	$ 1,396
New York City net operating loss carryforward credit	334	0	0
Deferred tax assets	$ 590	$ 916	$ 1,396