MORTGAGE SERVICING RIGHTS AND MSR FINANCING RECEIVABLES - Schedule of Type of Advances Included in the Servicer Advances Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Transfers and Servicing of Financial Assets [Abstract]
Principal and interest advances	$ 592,660	$ 616,801
Escrow advances (taxes and insurance advances)	1,283,083	1,442,697
Foreclosure advances	775,190	767,171
Total	2,650,933	2,826,669
Servicer advances receivable related to agency MSRs	529,600	585,000
Servicer advances receivable related to Ginnie Mae MSRS, recoverable from Ginnie Mae	372,200	405,600
Servicer advances, unamortized discount and accrual	$ 64,500	$ 66,400