MORTGAGE SERVICING RIGHTS AND MSR FINANCING RECEIVABLES - Schedule of Advances Included in Servicing Advances Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Transfers and Servicing [Abstract]
Principal and interest advances	$ 616,801	$ 664,495
Escrow advances (taxes and insurance advances)	1,442,697	1,426,409
Foreclosure advances	767,171	754,073
Total	2,826,669	2,844,977
Servicer advances receivable related to agency MSRs	585,000	526,500
Servicer advances receivable related to Ginnie Mae MSRS, recoverable from Ginnie Mae	405,600	261,800
Servicer advances, unamortized discount and accrual	$ 66,400	$ 19,500