Debt and Preferred Equity Investments - Preferred Equity Investments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Preferred equity investment
Aggregate weighted average current yield (as a percent)	7.87%
Carrying Value	$ 1,783,336	$ 1,580,306
Preferred Equity, April 2021
Preferred equity investment
Future Funding Obligations	0
Senior Financing	272,000
Carrying Value	133,050	142,921
Preferred Equity, June 2022
Preferred equity investment
Future Funding Obligations	0
Senior Financing	1,712,750
Carrying Value	150,273	98,065
Preferred Equity, February 2027
Preferred equity investment
Future Funding Obligations	0
Senior Financing	250,000
Carrying Value	$ 100,000	0
Preferred equity investments
Preferred equity investment
Aggregate weighted average current yield (as a percent)	9.87%
Future Funding Obligations	$ 0
Senior Financing	2,234,750
Carrying Value	383,323	240,986
Allowance for loan loss	(15,631)	(1,750)
Total after allowance for loan loss	$ 367,692	$ 239,236