SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)				3 Months Ended		6 Months Ended	9 Months Ended
	Nov. 01, 2021 $ / shares	Jul. 12, 2021 USD ($) $ / shares shares	Oct. 23, 2019 $ / shares	Sep. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2021	Sep. 30, 2021 USD ($) segment $ / shares shares	Sep. 30, 2020 USD ($) $ / shares shares	Jun. 04, 2021 USD ($) $ / shares shares	Jun. 01, 2021 $ / shares	May 13, 2021 $ / shares	Jan. 04, 2021 $ / shares	Dec. 31, 2020 USD ($)	Dec. 07, 2020 $ / shares	Jan. 02, 2020 $ / shares	Dec. 04, 2019 $ / shares
Accounting Policies [Abstract]
Purchase price per share as percent of estimated value				95.00%			95.00%
Estimated value per share of Company's common stock (in dollars per share) | $ / shares											$ 10.77			$ 10.74		$ 11.65
Special dividends (in dollars per share) | $ / shares			$ 0.80
Purchase price per share (in dollars per share) | $ / shares										$ 10.23		$ 10.21			$ 11.07
Period of termination notice							10 days
Subsidiary, Sale of Stock [Line Items]
Stock repurchased (in dollars per share) | $ / shares		$ 10.34							$ 10.34
Redemptions of common stock (in shares) | shares		26,377,990
Redemptions of common stock		$ 272,700,000		$ 307,717,000	$ 2,343,000		$ 313,800,000	$ 8,635,000
Share holding term							1 year
Period of increase or decrease of funding available for redemption							10 days
Maximum percentage of weighted-average shares outstanding available for redemption during current calendar year							5.00%
Maximum number of weighted-average shares outstanding available for redemption during current calendar year (in shares) | shares				500,000			500,000
Share redemption program, special redemptions (in shares) | shares				500,000			500,000
Maximum percentage of weighted-average shares outstanding available for redemption during any calendar year							5.00%
Redemption price percentage of most recent estimated value per share				96.00%		95.00%
Redeemable common stock				$ 87,445,000			$ 87,445,000						$ 46,723,000
Potentially dilutive securities (in shares) | shares				0	0		0	0
Distributions declared per share (in dollars per share) | $ / shares				$ 0.150	$ 0.150		$ 0.448	$ 0.448
Common share, distribution rate for share per month, declared (in dollars per share) | $ / shares							$ 0.04983333	$ 0.04983333
Number of reportable segments | segment							1
Grants of rent deferrals, COVID-19				$ 4,100,000			$ 4,100,000
Grants of rental abatements, COVID-19				2,400,000			2,400,000
Deferred lease concessions, COVID-19				1,900,000			1,900,000
Reserve for payments not probable to collect, COVID-19				1,500,000			1,500,000
Reversal of rental income for abatements granted to tenants, COVID-19				100,000	$ 300,000		700,000	$ 900,000
Available for All Redemptions in the Remainder of 2021
Subsidiary, Sale of Stock [Line Items]
Redeemable common stock				54,600,000			54,600,000
Available for All Redemptions in 2022
Subsidiary, Sale of Stock [Line Items]
Redeemable common stock				32,800,000			32,800,000
Subsequent Event
Accounting Policies [Abstract]
Purchase price per share as percent of estimated value	95.00%
Estimated value per share of Company's common stock (in dollars per share) | $ / shares	$ 10.78
Purchase price per share (in dollars per share) | $ / shares	$ 10.24
Subsidiary, Sale of Stock [Line Items]
Redemption price percentage of most recent estimated value per share	96.00%
Maximum
Subsidiary, Sale of Stock [Line Items]
Number of shares authorized to be repurchased (in shares) | shares									33,849,130
Authorized amount									$ 350,000,000
Share redemption program, additional amount				10,000,000			10,000,000
Share redemption program, special redemptions				$ 10,000,000			$ 10,000,000