SIGNIFICANT ACCOUNTING POLICIES - Summary of Estimated Useful Lives of Assets (Details)	12 Months Ended
	Dec. 31, 2017
Building | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	30 years
Building | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	40 years
Site improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	1 year
Site improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	28 years