Represents acquisition discounts.

No definition available.

Name:	cmct_AcquisitionDiscount
Namespace Prefix:	cmct_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the information pertaining to discount adjustment between carrying value of our loans and estimated fair market value.

+ References

No definition available.

+ Details

Name:	cmct_BusinessAcquisitionDiscountAdjustmentRecognizedAsDifferenceBetweenCarryingValueOfLoansAndEstimatedFairMarketValue
Namespace Prefix:	cmct_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of unamortized discount of loans acquired in connection with business combinations in a disposal group.

+ References

No definition available.

+ Details

Name:	cmct_DisposalGroupIncludingDiscontinuedOperationLoansAcquisitionDiscountsUnamortized
Namespace Prefix:	cmct_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Loan And Leases Receivable, Nonaccrual Loan And Lease Status, Past Due Period

+ References

No definition available.

+ Details

Name:	cmct_LoanAndLeasesReceivableNonaccrualLoanAndLeaseStatusPastDuePeriod
Namespace Prefix:	cmct_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Loans Receivable Held-For-Investment, Impairment

+ References

No definition available.

+ Details

Name:	cmct_LoansReceivableHeldForInvestmentImpairment
Namespace Prefix:	cmct_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6378536&loc=d3e10092-111533

+ Details

Name:	us-gaap_UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cmct_CommercialMortgageLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=cmct_PMCCommercialTrustMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Loans Receivable (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2015	Mar. 11, 2014
Loans receivable
Unamortized retained loan discounts	$ 7,348,000		$ 7,234,000
Loan receivable, nonaccrual, past due period (more than)	60 days
Impairment on loans receivable	$ 57,000	$ 0
SBA 7(a) loans receivable, subject to secured borrowings
Loans receivable
Unamortized acquisition discounts related to sold loans				$ 15,951,000
PMC Commercial
Loans receivable
Discount on acquisition					$ 33,907,000
Acquisition discount	$ 842,000		$ 884,000