REAL ESTATE AND RELATED LEASE INTANGIBLES, NET - Real Estate Properties Sold (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) property	Sep. 30, 2014 USD ($) property	Sep. 30, 2015 USD ($) property Condominium_Unit	Sep. 30, 2014 USD ($) property Condominium_Unit	Dec. 31, 2014 USD ($)
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate			$ 84,656	$ 103,462
Real estate and related lease intangibles, net	$ 791,577		791,577		$ 768,986
Realized Gain/(Loss)	6,406	$ 8,471	21,347	24,225
2015 Disposal Properties
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate			95,966
Real estate and related lease intangibles, net	74,619		74,619
Realized Gain/(Loss)			21,347
2015 Disposal Properties | Net Lease | Plattsmouth, NE
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate			8,440
Real estate and related lease intangibles, net	$ 7,983		7,983
Realized Gain/(Loss)			$ 457
Number of properties disposed | property	1		1
Number of units sold | Condominium_Unit			0
2015 Disposal Properties | Net Lease | Worthington, MN
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate			$ 8,793
Real estate and related lease intangibles, net	$ 8,321		8,321
Realized Gain/(Loss)			$ 472
Number of properties disposed | property	1		1
Number of units sold | Condominium_Unit			0
2015 Disposal Properties | Net Lease | Loveland, CO
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate			$ 6,249
Real estate and related lease intangibles, net	$ 5,600		5,600
Realized Gain/(Loss)			$ 649
Number of properties disposed | property	1		1
Number of units sold | Condominium_Unit			0
2015 Disposal Properties | Net Lease | Village of Menomonee Falls, WI
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate			$ 18,186
Real estate and related lease intangibles, net	$ 16,827		16,827
Realized Gain/(Loss)			$ 1,359
Number of properties disposed | property	1		1
Number of units sold | Condominium_Unit			0
2015 Disposal Properties | Condominium | Las Vegas, NV
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate			$ 31,997
Real estate and related lease intangibles, net	$ 18,617		18,617
Realized Gain/(Loss)			$ 13,380
Number of properties disposed | property	0		0
Number of units sold | Condominium_Unit			72
2015 Disposal Properties | Condominium | Miami, FL
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate			$ 22,301
Real estate and related lease intangibles, net	$ 17,271		17,271
Realized Gain/(Loss)			$ 5,030
Number of properties disposed | property	0		0
Number of units sold | Condominium_Unit			74
2014 Disposal Properties
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate				103,462
Real estate and related lease intangibles, net		79,237		79,237
Realized Gain/(Loss)				24,225
2014 Disposal Properties | Net Lease | Tilton, NH
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate				8,432
Real estate and related lease intangibles, net		$ 6,743		6,743
Realized Gain/(Loss)				$ 1,689
Number of properties disposed | property		1		1
Number of units sold | Condominium_Unit				0
2014 Disposal Properties | Net Lease | Yulee, FL
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate				$ 1,436
Real estate and related lease intangibles, net		$ 1,246		1,246
Realized Gain/(Loss)				$ 190
Number of properties disposed | property		1		1
Number of units sold | Condominium_Unit				0
2014 Disposal Properties | Net Lease | Middleburg, FL
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate				$ 1,262
Real estate and related lease intangibles, net		$ 1,077		1,077
Realized Gain/(Loss)				$ 185
Number of properties disposed | property		1		1
Number of units sold | Condominium_Unit				0
2014 Disposal Properties | Net Lease | Jonesboro, AR
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate				$ 9,413
Real estate and related lease intangibles, net		$ 8,016		8,016
Realized Gain/(Loss)				$ 1,397
Number of properties disposed | property		1		1
Number of units sold | Condominium_Unit				0
2014 Disposal Properties | Net Lease | Mt. Juliet, TN
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate				$ 10,167
Real estate and related lease intangibles, net		$ 8,724		8,724
Realized Gain/(Loss)				$ 1,443
Number of properties disposed | property		1		1
Number of units sold | Condominium_Unit				0
2014 Disposal Properties | Other | Richmond, VA
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate				$ 16,793
Real estate and related lease intangibles, net		$ 15,642		15,642
Realized Gain/(Loss)				$ 1,151
Number of properties disposed | property		1		1
Number of units sold | Condominium_Unit				0
2014 Disposal Properties | Condominium | Las Vegas, NV
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate				$ 46,213
Real estate and related lease intangibles, net		$ 30,035		30,035
Realized Gain/(Loss)				$ 16,178
Number of properties disposed | property		0		0
Number of units sold | Condominium_Unit				96
2014 Disposal Properties | Condominium | Miami, FL
Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of real estate				$ 9,746
Real estate and related lease intangibles, net		$ 7,754		7,754
Realized Gain/(Loss)				$ 1,992
Number of properties disposed | property		0		0
Number of units sold | Condominium_Unit				34