INTANGIBLE ASSETS - Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Intangible Assets [Line Items]
Intangible assets, total cost	$ 177,581	$ 196,417
Intangible assets, accumulated amortization	(92,730)	(65,069)
Intangible assets, net	84,851	131,348
Acquired lease intangibles, net	22,263	31,783
Below market leases acquired
Intangible Assets [Line Items]
Acquired lease intangibles, gross	44,757	49,655
Acquired lease intangibles, accumulated amortization	(22,494)	(17,872)
Acquired lease intangibles, net	22,263	31,783
In-place lease value
Intangible Assets [Line Items]
Intangible assets, total cost	167,357	181,887
Intangible assets, accumulated amortization	(84,123)	(53,376)
Intangible assets, net	83,234	128,511
Tenant relationship value
Intangible Assets [Line Items]
Intangible assets, total cost	5,268	9,564
Intangible assets, accumulated amortization	(4,815)	(8,551)
Intangible assets, net	453	1,013
Above market leases acquired
Intangible Assets [Line Items]
Intangible assets, total cost	4,956	4,966
Intangible assets, accumulated amortization	(3,792)	(3,142)
Intangible assets, net	$ 1,164	$ 1,824