220 Central Park South - Narrative (Details) ft² in Thousands, $ in Thousands	12 Months Ended			15 Months Ended
	Dec. 31, 2019 USD ($) ft² unit	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2019 USD ($) ft² unit
Real Estate [Line Items]
Net gains on sale of real estate	$ 2,571,099	$ 0	$ 0
Income tax expense	103,439	37,633	42,375
Repayments of construction loans payable	$ 438,935	74,609	$ 0
220 Central Park South
Real Estate [Line Items]
Square footage of real estate property (in sqft) | ft²	397			397
Development costs, cumulative	$ 1,450,000			$ 1,450,000
Development costs expended	$ 1,373,000			$ 1,373,000
Number of units sold | unit	54			65
Cash proceeds from sale of real estate	$ 1,605,356			$ 1,820,132
Net gains on sale of real estate	604,393
Income tax expense	101,828	$ 13,888
Repayments of construction loans payable	737,000
Construction loan	$ 950,000			$ 950,000
Percentage of units sold or under sales contract	91.00%