Loans and Preferred Equity Held for Investment, net and Loans Held for Sale - Summary of Loans and Preferred Equity Held for Investment by Year of Origination and Credit Quality Risk Ranking (Details) $ in Thousands	Jun. 30, 2020 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 0
2019	1,282,367
2018	932,652
2017	45,701
2016	0
Prior	34,375
Total	2,295,095
Senior loans
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	1,189,514
2018	759,426
2017	33,581
2016	0
Prior	29,846
Total	2,012,367
Senior loans | Average risk
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	265,249
2018	296,631
2017	33,581
2016	0
Prior	0
Total	595,461
Senior loans | High risk/delinquent/potential for loss
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	924,265
2018	462,795
2017	0
2016	0
Prior	0
Total	1,387,060
Senior loans | Impaired/defaulted/loss likely
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	29,846
Total	29,846
Mezzanine loans
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	79,053
2018	54,534
2017	12,120
2016	0
Prior	4,529
Total	150,236
Mezzanine loans | Average risk
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Total	0
Mezzanine loans | High risk/delinquent/potential for loss
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	79,053
2018	54,534
2017	12,120
2016	0
Prior	4,529
Total	150,236
Preferred equity interests
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	13,800
2018	118,692
2017	0
2016	0
Prior	0
Total	132,492
Preferred equity interests | High risk/delinquent/potential for loss
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	13,800
2018	18,007
2017	0
2016	0
Prior	0
Total	31,807
Preferred equity interests | Impaired/defaulted/loss likely
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	100,685
2017	0
2016	0
Prior	0
Total	$ 100,685