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RELATED-PARTY TRANSACTIONS (Details) - USD ($)					3 Months Ended		6 Months Ended
RELATED-PARTY TRANSACTIONS (Details) - USD ($)	Dec. 18, 2017	Jun. 12, 2017	Sep. 14, 2016	Oct. 01, 2015	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Related-party transactions
Due to related parties					$ 9,203,000		$ 9,203,000		$ 8,814,000
Wholesaling agreement, percent of selling price fee per share							2.75%
Share repurchase								$ 576,000,000
CIM Urban REIT Management, L.P. \| Asset Management Fees
Related-party transactions
Fees					4,460,000	$ 6,130,000	$ 8,875,000	12,544,000
Due to related parties					4,467,000		4,467,000		4,714,000
CIM Urban REIT Management, L.P. \| Property Management Fees
Related-party transactions
Fees					$ 1,083,000	1,306,000	$ 2,205,000	2,738,000
CIM Urban REIT Management, L.P. \| 0 - 500,000,000
Related-party transactions
Quarterly fee percentage					0.25%		0.25%
CIM Urban REIT Management, L.P. \| 0 - 500,000,000 \| Minimum
Related-party transactions
Daily average adjusted fair value of investments					$ 0		$ 0
CIM Urban REIT Management, L.P. \| 0 - 500,000,000 \| Maximum
Related-party transactions
Daily average adjusted fair value of investments					$ 500,000,000		$ 500,000,000
CIM Urban REIT Management, L.P. \| 500,000,000 - 1,000,000,000
Related-party transactions
Quarterly fee percentage					0.2375%		0.2375%
CIM Urban REIT Management, L.P. \| 500,000,000 - 1,000,000,000 \| Minimum
Related-party transactions
Daily average adjusted fair value of investments					$ 500,000,000		$ 500,000,000
CIM Urban REIT Management, L.P. \| 500,000,000 - 1,000,000,000 \| Maximum
Related-party transactions
Daily average adjusted fair value of investments					$ 1,000,000,000		$ 1,000,000,000
CIM Urban REIT Management, L.P. \| 1,000,000,000 - 1,500,000,000
Related-party transactions
Quarterly fee percentage					0.225%		0.225%
CIM Urban REIT Management, L.P. \| 1,000,000,000 - 1,500,000,000 \| Minimum
Related-party transactions
Daily average adjusted fair value of investments					$ 1,000,000,000		$ 1,000,000,000
CIM Urban REIT Management, L.P. \| 1,000,000,000 - 1,500,000,000 \| Maximum
Related-party transactions
Daily average adjusted fair value of investments					$ 1,500,000,000		$ 1,500,000,000
CIM Urban REIT Management, L.P. \| 1,500,000,000 - 4,000,000,000
Related-party transactions
Quarterly fee percentage					0.2125%		0.2125%
CIM Urban REIT Management, L.P. \| 1,500,000,000 - 4,000,000,000 \| Minimum
Related-party transactions
Daily average adjusted fair value of investments					$ 1,500,000,000		$ 1,500,000,000
CIM Urban REIT Management, L.P. \| 1,500,000,000 - 4,000,000,000 \| Maximum
Related-party transactions
Daily average adjusted fair value of investments					$ 4,000,000,000		$ 4,000,000,000
CIM Urban REIT Management, L.P. \| 4,000,000,000 - 20,000,000,000
Related-party transactions
Quarterly fee percentage					0.10%		0.10%
CIM Urban REIT Management, L.P. \| 4,000,000,000 - 20,000,000,000 \| Minimum
Related-party transactions
Daily average adjusted fair value of investments					$ 4,000,000,000		$ 4,000,000,000
CIM Urban REIT Management, L.P. \| 4,000,000,000 - 20,000,000,000 \| Maximum
Related-party transactions
Daily average adjusted fair value of investments					20,000,000,000		20,000,000,000
CIM Management Entities
Related-party transactions
Due to related parties					2,313,000		2,313,000		2,986,000
CIM Management Entities \| Personnel Fees
Related-party transactions
Fees					1,533,000	2,556,000	3,267,000	4,686,000
CIM Management Entities \| Lease Commission Fees
Related-party transactions
Fees					30,000	210,000	219,000	371,000
CIM Management Entities \| Construction Management Fees
Related-party transactions
Fees					86,000	91,000	441,000	275,000
CIM Management Entities And Related Parties
Related-party transactions
Due to related parties					15,000		15,000
Due from related parties									849,000
CIM Service Provider, LLC \| Base Service Fee
Related-party transactions
Fees					269,000	265,000	539,000	530,000
Fees payable per year under agreement					1,000,000		1,000,000
CIM Service Provider, LLC \| Master Services Agreement
Related-party transactions
Due to related parties					1,196,000		1,196,000		$ 1,963,000
Compensation expensed for performing other services					697,000	560,000	1,555,000	1,622,000
CIM SBA Staffing, LLC \| Personnel Fees
Related-party transactions
Due to related parties					1,212,000		1,212,000
Deferred personnel costs					88,000	110,000	136,000	154,000
CIM SBA Staffing, LLC \| Expenses Related to Lending Segment Subject to Reimbursement
Related-party transactions
Fees					639,000	784,000	1,240,000	1,628,000
CIM SBA Staffing, LLC \| Expenses Related to Corporate Services Subject to Reimbursement
Related-party transactions
Fees					78,000	124,000	145,000	239,000
CIM Management Entities Affiliate
Related-party transactions
Lease renewal term				5 years
Rental and other property income					$ 27,000	$ 27,000	$ 54,000	$ 54,000
December 2017 Share Repurchase \| Urban Partners II, LLC \| Common Stock
Related-party transactions
Stock repurchased and retired (in shares)	14,090,909	26,181,818	3,628,116
Share repurchase	$ 310,000,000	$ 576,000,000	$ 79,819,000
Aggregate purchase price (in usd per share)	$ 22	$ 22	$ 22