BUSINESS ACQUISITIONS - Narrative (Details) $ in Thousands							3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 20, 2021 USD ($)	Aug. 23, 2021 USD ($)	Apr. 10, 2020 USD ($)	Oct. 01, 2019 USD ($) employee	Sep. 03, 2019 USD ($) earnoutPayment	May 01, 2019 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Aug. 19, 2019
Business Acquisition [Line Items]
Bargain purchase gain									$ 6,024	$ 0	$ 49,539
Effective settlement of preexisting relationships									0	0	4,919
Contingent consideration							$ 4,951		4,951	14,247
Goodwill							85,199		85,199	29,468	29,468
Intangible assets							143,133		143,133	34,125
Covius Holdings Inc.
Business Acquisition [Line Items]
Goodwill						$ 11,800
Strategic investment						27,300
Subordinated debt facility						$ 35,000
Note receivable, term						4 years
Intangible assets						$ 3,600
Caliber Home Loans Inc
Business Acquisition [Line Items]
Cash consideration		$ 1,318,000
Bargain purchase gain		$ 3,300						$ 3,300	6,000
Goodwill (bargain purchase gain)							$ 2,700
Revenue of acquiree									659,800
Net income of acquiree									25,900
Transition, integration, relocation, and training costs incurred									9,600
Finite-lived intangible assets, useful life		4 years 9 months 18 days
Genesis
Business Acquisition [Line Items]
Cash consideration	$ 1,630,000
Revenue of acquiree									4,200
Net income of acquiree									$ 1,400
Equity interest acquired							100.00%		100.00%
Transition, integration, relocation, and training costs incurred									$ 6,700
Finite-lived intangible assets, useful life	8 years 6 months
Goodwill	$ 55,700
Ditech Acquisition
Business Acquisition [Line Items]
Cash consideration				$ 1,213,300
Bargain purchase gain											49,500
Transition, integration, relocation, and training costs incurred											22,900
Number of employees | employee				1,100
Effective settlement of preexisting relationships				$ 4,900
Guardian
Business Acquisition [Line Items]
Cash consideration					$ 7,600
Contingent consideration, high					17,500
Contingent consideration					13,900		$ 0		$ 0	$ 0	$ 13,893
Goodwill					5,100
Goodwill, expected tax deductible amount					5,100
Guardian | NRZ Guardian Purchaser LLC
Business Acquisition [Line Items]
Cash consideration			$ 1,900		$ 7,600
Equity interest acquired					100.00%							100.00%
Number of earnout payments | earnoutPayment					4
Contingent consideration, high					$ 17,500