REAL ESTATE AND RELATED LEASE INTANGIBLES, NET - Schedule of Real Estate Properties Acquired (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Business Acquisition [Line Items]
Purchase Price	$ 16,008	$ 140,234
Land | St. Paul, MN
Business Acquisition [Line Items]
Purchase Price	$ 200
Ownership Interest (percent)	100.00%
Net Lease | Dimmitt, TX
Business Acquisition [Line Items]
Purchase Price	$ 1,319
Ownership Interest (percent)	100.00%
Net Lease | Philo, IL
Business Acquisition [Line Items]
Purchase Price	$ 1,156
Ownership Interest (percent)	100.00%
Net Lease | St.Charles, MN
Business Acquisition [Line Items]
Purchase Price	$ 1,198
Ownership Interest (percent)	100.00%
Net Lease | San Antonio, TX
Business Acquisition [Line Items]
Purchase Price	$ 1,096
Ownership Interest (percent)	100.00%
Net Lease | Borger, TX
Business Acquisition [Line Items]
Purchase Price	$ 978
Ownership Interest (percent)	100.00%
Net Lease | Champaign, IL
Business Acquisition [Line Items]
Purchase Price	$ 1,324
Ownership Interest (percent)	100.00%
Net Lease | Decatur, IL
Business Acquisition [Line Items]
Purchase Price	$ 1,181
Ownership Interest (percent)	100.00%
Net Lease | Flora Vista, NM
Business Acquisition [Line Items]
Purchase Price	$ 1,305
Ownership Interest (percent)	100.00%
Net Lease | Mountain Grove, MO
Business Acquisition [Line Items]
Purchase Price	$ 1,279
Ownership Interest (percent)	100.00%
Net Lease | Rantoul, IL
Business Acquisition [Line Items]
Purchase Price	$ 1,204
Ownership Interest (percent)	100.00%
Net Lease | Decatur, IL
Business Acquisition [Line Items]
Purchase Price	$ 1,365
Ownership Interest (percent)	100.00%
Net Lease | Cape Girardeau, MO
Business Acquisition [Line Items]
Purchase Price	$ 1,281
Ownership Interest (percent)	100.00%
Net Lease | Linn, MO
Business Acquisition [Line Items]
Purchase Price	$ 1,122
Ownership Interest (percent)	100.00%
Net Lease | Jacksonville, NC
Business Acquisition [Line Items]
Purchase Price		$ 7,877
Ownership Interest (percent)		100.00%
Net Lease | Iberia, MO
Business Acquisition [Line Items]
Purchase Price		$ 1,328
Ownership Interest (percent)		100.00%
Net Lease | Isle, MN
Business Acquisition [Line Items]
Purchase Price		$ 1,078
Ownership Interest (percent)		100.00%
Net Lease | Pine Island, MN
Business Acquisition [Line Items]
Purchase Price		$ 1,142
Ownership Interest (percent)		100.00%
Net Lease | Kings Mountain, NC
Business Acquisition [Line Items]
Purchase Price		$ 21,241
Ownership Interest (percent)		100.00%
Net Lease | Village of Menomonee Falls, WI
Business Acquisition [Line Items]
Purchase Price		$ 17,050
Ownership Interest (percent)		100.00%
Net Lease | Rockland, MA
Business Acquisition [Line Items]
Purchase Price		$ 7,316
Ownership Interest (percent)		100.00%
Net Lease | Crawfordsville, IA
Business Acquisition [Line Items]
Purchase Price		$ 6,000
Ownership Interest (percent)		100.00%
Net Lease | Boardman Township, OH
Business Acquisition [Line Items]
Purchase Price		$ 5,400
Ownership Interest (percent)		100.00%
Net Lease | Hilliard, OH
Business Acquisition [Line Items]
Purchase Price		$ 6,384
Ownership Interest (percent)		100.00%
Net Lease | Weathersfield Township, OH
Business Acquisition [Line Items]
Purchase Price		$ 5,200
Ownership Interest (percent)		100.00%
Net Lease | Rotterdam, NY
Business Acquisition [Line Items]
Purchase Price		$ 12,000
Ownership Interest (percent)		100.00%
Net Lease | Wheaton, MO
Business Acquisition [Line Items]
Purchase Price		$ 970
Ownership Interest (percent)		100.00%
Net Lease | Paynesville, MN
Business Acquisition [Line Items]
Purchase Price		$ 1,254
Ownership Interest (percent)		100.00%
Net Lease | Loveland, CO
Business Acquisition [Line Items]
Purchase Price		$ 5,600
Ownership Interest (percent)		100.00%
Net Lease | Battle Lake, MN
Business Acquisition [Line Items]
Purchase Price		$ 1,098
Ownership Interest (percent)		100.00%
Net Lease | Yorktown, TX
Business Acquisition [Line Items]
Purchase Price		$ 1,207
Ownership Interest (percent)		100.00%
Net Lease | St. Francis, MN
Business Acquisition [Line Items]
Purchase Price		$ 1,117
Ownership Interest (percent)		100.00%
Net Lease | Red Oak, IA
Business Acquisition [Line Items]
Purchase Price		$ 1,185
Ownership Interest (percent)		100.00%
Net Lease | Zapata, TX
Business Acquisition [Line Items]
Purchase Price		$ 1,150
Ownership Interest (percent)		100.00%
Net Lease | Aurora, MN
Business Acquisition [Line Items]
Purchase Price		$ 952
Ownership Interest (percent)		100.00%
Net Lease | Canyon Lake, TX
Business Acquisition [Line Items]
Purchase Price		$ 1,377
Ownership Interest (percent)		100.00%
Net Lease | Wheeler, TX
Business Acquisition [Line Items]
Purchase Price		$ 1,075
Ownership Interest (percent)		100.00%
Net Lease | Bridgeport, IL
Business Acquisition [Line Items]
Purchase Price		$ 1,186
Ownership Interest (percent)		100.00%
Net Lease | Peoria, IL
Business Acquisition [Line Items]
Purchase Price		$ 1,226
Ownership Interest (percent)		100.00%
Net Lease | Pleasanton, TX
Business Acquisition [Line Items]
Purchase Price		$ 1,316
Ownership Interest (percent)		100.00%
Net Lease | Warren, MN
Business Acquisition [Line Items]
Purchase Price		$ 1,055
Ownership Interest (percent)		100.00%
Net Lease | Tremont, IL
Business Acquisition [Line Items]
Purchase Price		$ 1,150
Ownership Interest (percent)		100.00%
Other | Grand Rapids, MI
Business Acquisition [Line Items]
Purchase Price		$ 9,300
Ownership Interest (percent)		97.00%
Other | Grand Rapids, MI
Business Acquisition [Line Items]
Purchase Price		$ 6,300
Ownership Interest (percent)		97.00%
Other | Wayne, NJ
Business Acquisition [Line Items]
Purchase Price		$ 9,700
Ownership Interest (percent)		100.00%