EXCESS MORTGAGE SERVICING RIGHTS - Schedule of Activity Related to the Carrying Value of Investments in Excess MSRs (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Carrying Value of Investments in Excess MSRs
Beginning balance	$ 6,858,803
Ending balance	8,626,409
Excess MSRs
Carrying Value of Investments in Excess MSRs
Beginning balance	259,198
Interest income	20,605
Other income	37
Proceeds from repayments	(21,063)
Proceeds from sales	(997)
Change in fair value	(1,564)
Ending balance	256,216
Excess MSRs | Mr. Cooper
Carrying Value of Investments in Excess MSRs
Beginning balance	257,573
Interest income	20,094
Other income	37
Proceeds from repayments	(20,909)
Proceeds from sales	(997)
Change in fair value	(1,119)
Ending balance	254,679
Excess MSRs | SLS
Carrying Value of Investments in Excess MSRs
Beginning balance	1,625
Interest income	511
Other income	0
Proceeds from repayments	(154)
Proceeds from sales	0
Change in fair value	(445)
Ending balance	$ 1,537