REAL ESTATE AND RELATED LEASE INTANGIBLES, NET - Real Estate Properties Sold (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) property		Mar. 31, 2017 USD ($) property	Dec. 31, 2017 USD ($)
Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds	$ 87,885	[1]	$ 6,325
Net Book Value	980,859	[2]		$ 1,032,041
Realized Gain/(Loss)	31,010		2,331
2018 Disposal Properties
Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds	97,513
Net Book Value	66,504
Realized Gain/(Loss)	31,009
2018 Disposal Properties | Condominium | Las Vegas, NV
Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds	1,811
Net Book Value	732
Realized Gain/(Loss)	$ 1,079
Properties | property	0
Units Sold | property	2
Units Remaining | property	11
2018 Disposal Properties | Condominium | Miami, FL
Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds	$ 2,263
Net Book Value	1,792
Realized Gain/(Loss)	$ 471
Properties | property	0
Units Sold | property	8
Units Remaining | property	40
2018 Disposal Properties | Diversified | El Monte, CA
Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds	$ 71,807
Net Book Value	52,610
Realized Gain/(Loss)	$ 19,197
Properties | property	1
Units Sold | property	0
Units Remaining | property	0
2018 Disposal Properties | Diversified | Richmond, VA
Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds	$ 21,632
Net Book Value	11,370
Realized Gain/(Loss)	$ 10,262
Properties | property	1
Units Sold | property	0
Units Remaining | property	0
2017 Disposal Properties
Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds			6,325
Net Book Value			3,994
Realized Gain/(Loss)			2,331
2017 Disposal Properties | Condominium | Las Vegas, NV
Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds			4,200
Net Book Value			2,320
Realized Gain/(Loss)			$ 1,880
Properties | property			0
Units Sold | property			12
Units Remaining | property			47
2017 Disposal Properties | Condominium | Miami, FL
Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds			$ 2,125
Net Book Value			1,674
Realized Gain/(Loss)			$ 451
Properties | property			0
Units Sold | property			6
Units Remaining | property			82

[1] Includes cash proceeds received in the current year that relate to prior year sales of real estate of $1.4 million.

[2] Includes amounts relating to consolidated variable interest entities. See Note 3.