SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Accretion and Other Amortization (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accretion of discount and other amortization:
Accretion of servicer advance interest income		$ 352,316	$ 190,206	$ 4,421
Accretion of excess mortgage servicing rights income		134,565	49,180	40,921
Accretion of net discount on securities and loans	[1]	65,925	47,793	14,676
Amortization of deferred financing costs		(26,036)	(8,771)	(768)
Amortization of discount on notes payable		(1,472)	0	0
Accretion and other amortization		$ 525,298	$ 278,408	$ 59,250

[1] Includes accretion of the accretable yield on PCD loans.