Real Estate and Other Affiliates (Relevant Financial Information for The Summit) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) condominium_unit	Mar. 31, 2020 USD ($) condominium_unit	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Investments in and Advances to Affiliates [Line Items]
Total Assets	$ 9,154,162		$ 9,140,332
Total Liabilities	5,465,177		5,396,195
Total Equity	3,661,267	$ 3,772,598	3,715,023	$ 3,332,988
Revenues	190,580	175,175
Net income	(68,159)	(125,082)
The Summit
Investments in and Advances to Affiliates [Line Items]
Total Assets	334,970		310,855
Total Liabilities	203,138		209,968
Total Equity	131,832		$ 100,887
Revenues	90,873	39,836
Net income	32,089	10,559
Gross Margin	$ 33,049	$ 11,704
Number of units closed | condominium_unit	19	6