RELATED PARTY TRANSACTIONS - Summary of Fees and Expenses Incurred by Company (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Expensed:
Organization costs, incurred	$ 0	$ 0	$ 78
Advisory fee - fixed component, incurred	4,585	901	0
Advisory fee - performance component, incurred	2,913	723	0
Acquisition expense reimbursements, incurred	3,068	4,900	0
Other expenses reimbursements, incurred	1,963	1,195	185
Total	12,529	7,719	263
Organization costs, payable	78	78
Advisory fee - fixed component, payable	593	200
Advisory fee - performance component, payable	2,913	723
Acquisition expense reimbursements, payable	182	3,500
Other expenses reimbursements, payable	473	299
Total	4,239	4,800
Additional Paid in Capital:
Selling commissions, incurred	6,391	4,372	203
Dealer manager fees, incurred	5,306	4,430	253
Offering costs, incurred	7,150	13,270	849
Distribution fees - current, incurred	3,535	875	12
Distribution fees - trailing, incurred	9,010	7,063	394
Total	31,392	30,010	1,711
Selling commissions, payable	0	0
Dealer manager fees, payable	0	0
Offering costs, payable	21,269	14,119
Distribution fees - current, payable	389	168
Distribution fees payable to affiliates	16,467	7,457	394
Total	38,125	21,744
Advisor
Expensed:
Organization costs, payable	100
Additional Paid in Capital:
Offering costs incurred	21,300
Reimbursements	$ 1,800	$ 900	$ 200