SERVICER ADVANCE INVESTMENTS - Schedule of Interest Income Related to Investments in Servicer Advances (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Schedule of Equity Method Investments [Line Items]
Interest income	$ 253,735	$ 402,373
Servicer Advance Investments
Schedule of Equity Method Investments [Line Items]
Interest income, gross of amounts attributable to servicer compensation	13,961	(10,250)
Amounts attributable to base servicer compensation	(1,156)	882
Amounts attributable to incentive servicer compensation	(5,993)	(8,721)
Interest income	$ 6,812	$ (18,089)

Represents the total of interest and dividend income, including any amortization and accretion (as applicable) of discounts and premiums, earned from (1) loans and leases whether held-for-sale or held-in-portfolio; (2) investment securities; (3) federal funds sold; (4) securities purchased under agreements to resell; (5) investments in banker's acceptances, commercial paper, or certificates of deposit; (6) dividend income; or (7) other investments not otherwise specified herein.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.1-5)
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration