EXPENSES, CHANGE IN FAIR VALUE OF INVESTMENTS AND OTHER - Schedule of Accretion and Other Amortization (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accretion and other amortization:
Accretion of net discount on securities and loans	$ 5,293	$ 12,007
Accretion of servicer advances receivable discount and servicer advance investments	4,156	6,848
Accretion of excess mortgage servicing rights income	13,017	12,231
Amortization of deferred financing costs	(6,921)	(4,601)
Total accretion and other amortization	15,095	26,034
Secured Notes and Bonds Payable
Accretion and other amortization:
Amortization of discount	0	(1)
Corporate Debt
Accretion and other amortization:
Amortization of discount	$ (450)	$ (450)