MORTGAGE SERVICING RIGHTS AND MSR FINANCING RECEIVABLES - Schedule of Advances Included in Servicing Advances Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Total	$ 387,669	$ 398,820
Servicer Advances Receivable
Schedule of Equity Method Investments [Line Items]
Principal and interest advances	579,277	664,495
Escrow advances (taxes and insurance advances)	1,093,779	1,426,409
Foreclosure advances	833,680	754,073
Total	2,506,736	2,844,977
Servicer advances receivable related to agency MSRs	426,500	526,500
Servicer advances receivable related to Ginnie Mae MSRS, recoverable from Ginnie Mae	296,100	261,800
Servicer advances, unamortized discount and accrual	$ 72,500	$ 19,500