OPERATING PROPERTIES, REAL ESTATE HELD FOR SALE AND OTHER REAL ESTATE OWNED - Operating Properties and REO Assets (Details) $ in Thousands	Dec. 31, 2019 USD ($) Project	Dec. 31, 2018 USD ($)	Dec. 31, 2018 projects	Dec. 31, 2018 Project	Dec. 31, 2017 USD ($) Project
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Acquired Through Foreclosure and/or Guarantor Settlement	$ 59,406	$ 41,145
Acquired Through Purchase and Costs Incurred	47,501	34,550
Accumulated Depreciation	$ (2,862)	(684)
Number of Projects	15		16
Real Estate Acquired through Foreclosure	$ (104,045)	(75,011)			$ (64,641)
Real Estate Held for Sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Acquired Through Foreclosure and/or Guarantor Settlement	26,065	7,418
Acquired Through Purchase and Costs Incurred	61	0
Accumulated Depreciation	$ (621)	0
Number of Projects	8		8	8	2
Real Estate Acquired through Foreclosure	$ (25,505)	(7,418)			$ (5,853)
Operating Properties
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Acquired Through Foreclosure and/or Guarantor Settlement	0	0
Acquired Through Purchase and Costs Incurred	47,440	34,550
Accumulated Depreciation	$ (2,241)	(684)
Number of Projects	1		1	1	1
Real Estate Acquired through Foreclosure	$ (45,199)	(33,866)			$ (20,484)
Other Real Estate Owned
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Acquired Through Foreclosure and/or Guarantor Settlement	33,341	33,727
Acquired Through Purchase and Costs Incurred	0	0
Accumulated Depreciation	$ 0	0
Number of Projects	6		7	7	15
Real Estate Acquired through Foreclosure	$ (33,341)	(33,727)			$ (38,304)
California
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	3		3
Real Estate Acquired through Foreclosure	$ (45,588)	(34,255)
California | Real Estate Held for Sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	1		1
Real Estate Acquired through Foreclosure	$ (137)	(137)
California | Operating Properties
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	1		1
Real Estate Acquired through Foreclosure	$ (45,199)	(33,866)
California | Other Real Estate Owned
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	1		1
Real Estate Acquired through Foreclosure	$ (252)	(252)
Texas
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	1		2
Real Estate Acquired through Foreclosure	$ (2,760)	(2,977)
Texas | Real Estate Held for Sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	1		1
Real Estate Acquired through Foreclosure	$ (2,760)	(2,761)
Texas | Operating Properties
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	0		0
Real Estate Acquired through Foreclosure	$ 0	0
Texas | Other Real Estate Owned
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	0		1
Real Estate Acquired through Foreclosure	$ 0	(216)
Arizona
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	3		4
Real Estate Acquired through Foreclosure	$ (2,971)	(2,988)
Arizona | Real Estate Held for Sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	3		4
Real Estate Acquired through Foreclosure	$ (2,971)	(2,988)
Arizona | Operating Properties
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	0		0
Real Estate Acquired through Foreclosure	$ 0	0
Arizona | Other Real Estate Owned
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	0		0
Real Estate Acquired through Foreclosure	$ 0	0
Minnesota
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	2		2
Real Estate Acquired through Foreclosure	$ (1,532)	(1,532)
Minnesota | Real Estate Held for Sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	2		2
Real Estate Acquired through Foreclosure	$ (1,532)	(1,532)
Minnesota | Operating Properties
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	0		0
Real Estate Acquired through Foreclosure	$ 0	0
Minnesota | Other Real Estate Owned
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	0		0
Real Estate Acquired through Foreclosure	$ 0	0
Missouri
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects | Project	1
Real Estate Acquired through Foreclosure	$ (18,105)
Missouri | Real Estate Held for Sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects | Project	1
Real Estate Acquired through Foreclosure	$ (18,105)
Missouri | Operating Properties
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects | Project	0
Real Estate Acquired through Foreclosure	$ 0
Missouri | Other Real Estate Owned
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects | Project	0
Real Estate Acquired through Foreclosure	$ 0
New Mexico
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	5		5
Real Estate Acquired through Foreclosure	$ (33,089)	(33,259)
New Mexico | Real Estate Held for Sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	0		0
Real Estate Acquired through Foreclosure	$ 0	0
New Mexico | Operating Properties
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	0		0
Real Estate Acquired through Foreclosure	$ 0	0
New Mexico | Other Real Estate Owned
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Projects	5		5
Real Estate Acquired through Foreclosure	$ (33,089)	$ (33,259)