Variable Interest Entities - Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Accrued expenses and other liabilities	$ 343,353	$ 131,367
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Maximum loss	$ 246,905	32,466
Variable Interest Entity, Not Primary Beneficiary | Multifamily Loan Securitization, Liability
Variable Interest Entity [Line Items]
Maximum loss, percentage of loans	10.00%
Maximum loss	$ 50,901	0
Variable Interest Entity, Not Primary Beneficiary | Multifamily Loan Securitization
Variable Interest Entity [Line Items]
Accrued expenses and other liabilities	$ 463	$ 0