SUBSEQUENT EVENTS (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended		6 Months Ended
		Jul. 31, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Apr. 30, 2019	Jan. 31, 2019	Dec. 31, 2018	[2]	Oct. 31, 2018	Aug. 31, 2018	Mar. 31, 2018
Subsequent Event [Line Items]
Preferred stock, redemption price (in dollars per share)			$ 25.00		$ 25.00
Residential mortgages loans	[1]		$ 3,546,468		$ 3,546,468			$ 4,585,975
Subsequent Event
Subsequent Event [Line Items]
Preferred stock, redemption price (in dollars per share)		$ 25.00
Series C Preferred Stock
Subsequent Event [Line Items]
Preferred stock to be redeemed (in shares)				5,000,000.0
Series C Preferred Stock | Subsequent Event
Subsequent Event [Line Items]
Preferred stock to be redeemed (in shares)		7,000,000.0
Over-Allotment Option
Subsequent Event [Line Items]
Sale of stock, shares issued (in shares)			2,400,000		2,400,000
Over-Allotment Option | Subsequent Event
Subsequent Event [Line Items]
Sale of stock, shares issued (in shares)		1,700,000
Proceeds from sale of stock		$ 42,500
OBX Trust | Consolidated VIEs
Subsequent Event [Line Items]
Residential mortgages loans			$ 383,800		$ 383,800	$ 388,200	$ 394,000			$ 384,000	$ 383,500	$ 327,200
OBX Trust | Consolidated VIEs | Subsequent Event
Subsequent Event [Line Items]
Residential mortgages loans		$ 463,400

[1] ⁽⁴⁾  Includes $119.7 million and $97.5 million of residential mortgage loans held for sale, $41.9 million and $42.2 million of commercial mortgage loans held for sale and $26.9 million and $0 of corporate loans held for sale at June 30, 2019 and December 31, 2018, respectively.

[2] ⁽¹⁾  Derived from the audited consolidated financial statements at December 31, 2018.