VARIABLE INTEREST ENTITIES - Consolidated VIEs (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Loans held for sale, at fair value	$ 2,692,820	$ 4,656,338	$ 8,136,817	$ 8,873,736	$ 9,120,653	$ 6,955,424
Restricted cash	160,926		201,025
Servicing rights, at fair value	2,030,026		2,006,712
Prepaid expenses and other assets	115,452		140,315
Total assets	7,378,536		11,812,313
Warehouse and other lines of credit	2,529,436		7,457,199
Debt obligations, net	2,283,704		1,628,208
Total liabilities	6,300,039		10,182,953
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Loans held for sale, at fair value	481,950		2,557,490
Restricted cash	21,634		100,494
Servicing rights, at fair value	527,059		400,678
Prepaid expenses and other assets	34,711		17,756
Total assets	1,065,354		3,076,418
Warehouse and other lines of credit	500,000		2,600,000
Total liabilities	847,091		2,829,203
Variable Interest Entity, Primary Beneficiary | MSR Facilities
Variable Interest Entity [Line Items]
Debt obligations, net	116,874		15,000
Variable Interest Entity, Primary Beneficiary | Servicing advance facilities
Variable Interest Entity [Line Items]
Debt obligations, net	30,677		15,070
Variable Interest Entity, Primary Beneficiary | Term Notes
Variable Interest Entity [Line Items]
Debt obligations, net	$ 199,540		$ 199,133