220 Central Park South 220 CPS - Narrative (Details) ft² in Thousands, $ in Thousands	3 Months Ended		18 Months Ended
	Mar. 31, 2020 USD ($) ft² unit	Mar. 31, 2019 USD ($)	Mar. 31, 2020 USD ($) ft² unit
Real Estate [Line Items]
Income tax expense	$ 12,813	$ 29,743
220 Central Park South
Real Estate [Line Items]
Square footage of real estate property (in sqft) | ft²	397		397
Development costs	$ 1,450,000		$ 1,450,000
Development costs expended	$ 1,395,000		$ 1,395,000
Number of condominium units sold (unit) | unit	7		72
Cash proceeds from the sale of real estate	$ 191,216		$ 2,011,348
Net gain on sale of real estate	68,589
Income tax expense	$ 8,678