Debt and Preferred Equity Investments - Investment In Financing Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Carrying value	$ 1,076,542	$ 1,580,306
2020	346,320
2019	294,533
2018	266,185
Prior	169,504
1 - Low Risk Assets - Low probability of loss
Financing Receivable, Credit Quality Indicator [Line Items]
Carrying value	695,035	1,180,831
2020	346,320
2019	55,318
2018	209,941
Prior	83,456
2 - Watch List Assets - Higher potential for loss
Financing Receivable, Credit Quality Indicator [Line Items]
Carrying value	365,167	399,475
2020	0
2019	239,215
2018	56,244
Prior	69,708
3 - High Risk Assets - Loss more likely than not
Financing Receivable, Credit Quality Indicator [Line Items]
Carrying value	16,340	$ 0
2020	0
2019	0
2018	0
Prior	$ 16,340