Debt and Preferred Equity Investments - Debt Investment (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Aggregate weighted average current yield (as a percent)	6.51%
Debt Investments Held [Abstract]
Carrying Value	$ 1,072,711,000	$ 1,076,542,000
Carrying Value	1,072,711,000	1,076,542,000
Mezzanine Loan Due June 2023
Debt Investments Held [Abstract]
Loan interest income	0
Mezzanine Loan Due June 2024
Debt Investments Held [Abstract]
Amount participated out	12,000,000.0
Loan interest income	0
Mezzanine Loan Due March 2022
Debt Investments Held [Abstract]
Amount participated out	400,000
Debt Investments in Mortgage Loans
Debt Investments Held [Abstract]
Future Funding Obligations	97,187,000
Senior Financing	4,737,442,000
Allowance for loan loss	(13,213,000)	(13,213,000)
Carrying Value	806,456,000	816,756,000
Total fixed rate
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	2,913,158,000
Carrying Value	504,735,000	477,509,000
Total fixed rate | Mortgage/Mezzanine Loan Due October 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	56,248,000	56,244,000
Total fixed rate | Mezzanine Loan Due August 2022
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	280,000,000
Carrying Value	42,263,000	41,057,000
Total fixed rate | Mezzanine Loan Due June 2023
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	364,858,000
Carrying Value	225,367,000	225,204,000
Total fixed rate | Mezzanine Loan Due June 2023, 2
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	270,550,000
Carrying Value	62,240,000	0
Total fixed rate | Mezzanine Loan Due June 2024
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	105,000,000
Carrying Value	13,367,000	13,366,000
Total fixed rate | Mezzanine Loan, with an Initial Maturity Date of January 2025
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	95,000,000
Carrying Value	30,000,000	30,000,000
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of June 2027
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	1,712,750,000
Carrying Value	55,250,000	55,250,000
Total fixed rate | Mezzanine Loan With Initial Maturity Date Of December 2029
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	85,000,000
Carrying Value	20,000,000	20,000,000
Total fixed rate | Junior Mortgage Paid Off
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	32,888,000
Total fixed rate | Mezzanine Loan Paid Off
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	3,500,000
Total floating rate
Debt Investments Held [Abstract]
Future Funding Obligations	97,187,000
Senior Financing	1,824,284,000
Carrying Value	314,934,000	352,460,000
Total floating rate | Junior Mortgage Participation/Mezzanine Loan Due July 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	60,000,000
Carrying Value	15,751,000	15,733,000
Total floating rate | Mezzanine Loan Due July 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	61,744,000
Carrying Value	29,153,000	29,106,000
Total floating rate | Mezzanine Loan Due April 2022
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	275,000,000
Carrying Value	49,994,000	49,956,000
Total floating rate | Mezzanine Loan Due July 2021, 2
Debt Investments Held [Abstract]
Future Funding Obligations	5,287,000
Senior Financing	179,132,000
Carrying Value	37,148,000	35,318,000
Total floating rate | Mezzanine Loan Due March 2022
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	1,115,000,000
Carrying Value	130,774,000	127,915,000
Total floating rate | Mortgage/Mezzanine Loan Due May 2022
Debt Investments Held [Abstract]
Future Funding Obligations	4,565,000
Senior Financing	54,000,000
Carrying Value	7,384,000	6,958,000
Total floating rate | Mezzanine Loan Due December 2022
Debt Investments Held [Abstract]
Future Funding Obligations	36,887,000
Senior Financing	0
Carrying Value	21,211,000	14,011,000
Total floating rate | Mezzanine Loan Due May 2023
Debt Investments Held [Abstract]
Future Funding Obligations	50,448,000
Senior Financing	79,408,000
Carrying Value	23,519,000	19,889,000
Total floating rate | Mortgage Loan Paid Off
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	$ 0	$ 53,574,000