Debt and Preferred Equity Investments - Investment In Financing Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Carrying value	$ 1,097,202	$ 1,076,542
2020	0
2019	361,444
2018	297,924
Prior	437,834
1 - Low Risk Assets - Low probability of loss
Financing Receivable, Credit Quality Indicator [Line Items]
Carrying value	712,994	695,035
2020	0
2019	361,444
2018	56,639
Prior	294,911
2 - Watch List Assets - Higher potential for loss
Financing Receivable, Credit Quality Indicator [Line Items]
Carrying value	367,859	365,167
2020	0
2019	0
2018	241,285
Prior	126,574
3 - High Risk Assets - Loss more likely than not
Financing Receivable, Credit Quality Indicator [Line Items]
Carrying value	16,349	$ 16,340
2020	0
2019	0
2018	0
Prior	$ 16,349