EXCESS MORTGAGE SERVICING RIGHTS - Schedule of Excess Mortgage Servicing Rights (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Servicing Assets at Fair Value [Line Items]
Fair value	$ 8,694,868	$ 8,889,403
Excess mortgage servicing rights, at fair value
Servicing Assets at Fair Value [Line Items]
Fair value	282,976	321,803
Direct investments in Excess MSRs
Servicing Assets at Fair Value [Line Items]
Fair value	217,764	249,366
Excess MSR joint ventures
Servicing Assets at Fair Value [Line Items]
Fair value	$ 65,212	$ 72,437