SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (EPS Two-class Method) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net loss attributable to common stockholders									$ (7,499)	$ (23,508)	$ (3,272)
Undistributed net loss attributable to common stockholders									(10,878)	(28,515)	(7,192)
Common Class A
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net loss attributable to common stockholders	$ (488)	$ (1,519)	$ (1,537)	$ (914)	$ (9,183)	$ (2,914)	$ (22)	$ (1,573)	(4,458)	(13,729)	(1,480)
Less: Common Stock cash distributions declared									2,010	3,372	2,991
Undistributed net loss attributable to common stockholders									$ (6,468)	$ (17,101)	$ (4,471)
Net loss per common share, basic and diluted (in dollars per share)	$ (0.03)	$ (0.08)	$ (0.09)	$ (0.05)	$ (0.51)	$ (0.16)	$ 0	$ (0.09)	$ (0.25)	$ (0.77)	$ (0.09)
Weighted-average number of common shares outstanding, basic and diluted (in shares)									17,949,301	17,775,503	16,096,216
Common Class T
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net loss attributable to common stockholders	$ (334)	$ (1,038)	$ (1,048)	$ (621)	$ (6,191)	$ (2,049)	$ (282)	$ (1,294)	$ (3,041)	$ (9,779)	$ (1,792)
Less: Common Stock cash distributions declared									1,369	1,635	929
Undistributed net loss attributable to common stockholders									$ (4,410)	$ (11,414)	$ (2,721)
Net loss per common share, basic and diluted (in dollars per share)	$ (0.03)	$ (0.08)	$ (0.09)	$ (0.05)	$ (0.51)	$ (0.17)	$ (0.02)	$ (0.11)	$ (0.25)	$ (0.82)	$ (0.18)
Weighted-average number of common shares outstanding, basic and diluted (in shares)									12,241,271	11,864,178	9,797,325