SERVICER ADVANCE INVESTMENTS - Summary of Investments in Servicer Advances (Details) - Servicer Advance Joint Venture - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Investments in and Advances to Affiliates [Line Items]
Amortized Cost Basis	$ 3,955,375		$ 3,955,375		$ 5,687,635
Carrying Value	$ 4,044,802		$ 4,044,802		$ 5,706,593
Weighted Average Discount Rate	6.80%		6.80%		5.60%
Weighted Average Yield	7.20%		7.20%		5.50%
Weighted Average Life (Years)			5 years 1 month 17 days		4 years 7 months 1 day
Asset-backed securities, face amount, collateralized by servicer advances					$ 100,000
Asset-backed securities, carrying value, collateralized by servicer advances					$ 100,100
Changes in Fair Value Recorded in Other Income	$ 10,941	$ 21,606	$ 70,469	$ 4,328