220 Central Park South - Narrative (Details) ft² in Thousands, $ in Thousands		12 Months Ended			27 Months Ended
	Dec. 31, 2020 USD ($) ft²	Dec. 31, 2020 USD ($) ft² unit	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2020 USD ($) ft² unit
Real Estate [Line Items]
Net gains on sale of real estate		$ 0	$ 2,571,099	$ 0
Income tax expense		$ 36,630	103,439	$ 37,633
Percentage of units sold or under sales contract	91.00%
220 Central Park South
Real Estate [Line Items]
Square footage of real estate property (in sqft) | ft²	397	397			397
Development costs, cumulative	$ 1,480,000	$ 1,480,000			$ 1,480,000
Development costs expended	$ 1,455,000	$ 1,455,000			$ 1,455,000
Number of units sold | unit		35			100
Cash proceeds from sale of real estate		$ 1,049,360			$ 2,869,492
Net gains on sale of real estate		381,320			$ 1,066,937
Income tax expense		$ 49,221	$ 101,828