Line Of Credit Facility, Covenant, Liquid Assets, Amount

No definition available.

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

- Definition

Line Of Credit Facility, Covenant, Unfunded, Remaining Borrowing Capacity

+ References

No definition available.

+ Details

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

- Definition

Line Of Credit Facility, Fee Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	cmct_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line Of Credit Facility, Maximum Fee Amount

+ References

No definition available.

+ Details

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

- Definition

Line Of Credit Facility, Number Of Extensions

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Line Of Credit Facility, Remaining Borrowing Capacity, Reserve Amount

+ References

No definition available.

+ Details

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

- Definition

Represents the period that the credit facility may be extended under certain circumstances.

+ References

No definition available.

+ Details

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

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

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-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466204&loc=SL6036836-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
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-Section 45
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Topic 835
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-URI http://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

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

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cmct_UnsecuredRevolvingCreditFacilityDueMay2022Member
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Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

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- Details

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Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
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Data Type:	na
Balance Type:
Period Type:

- Details

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- Details

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- Details

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DEBT - 2018 Revolving Credit Facility and 2020 Unsecured Revolving Credit Facility Narrative (Details)	1 Months Ended
	Sep. 30, 2020 USD ($)	May 31, 2020 USD ($)	Oct. 31, 2018 USD ($) extensionOption	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 209,500,000
Line of Credit \| Revolving Credit Facility
Debt Instrument [Line Items]
Reserve amount	$ 15,000,000.0
Minimum balance of liquid assets				$ 15,000,000.0
Unfunded availability (up to)				5,000,000.0
Outstanding balance				107,000,000	$ 166,500,000
Amount available for future borrowings				87,500,000	$ 28,000,000.0
Line of Credit \| Revolving Credit Facility \| Unsecured Revolving Credit Facility Due May 2022
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 10,000,000.0
Amount available for future borrowings				10,000,000.0
Fixed interest rate		1.00%
Fee percentage for each advance made		1.12%
Maximum fee amount payable		$ 112,000
Debt outstanding				$ 0
Revolving Credit Facility
Debt Instrument [Line Items]
Effective interest rate				2.13%	2.20%
Number of extension options \| extensionOption			1
Extension option, term			1 year
Revolving Credit Facility \| Minimum
Debt Instrument [Line Items]
Unused commitment fee			0.15%
Revolving Credit Facility \| Maximum
Debt Instrument [Line Items]
Unused commitment fee			0.25%
Revolving Credit Facility \| Base rate \| Debt Instrument, During, Deferral Period
Debt Instrument [Line Items]
Interest rate margin	1.05%
Revolving Credit Facility \| Base rate \| Debt Instrument, Following, Deferral Period
Debt Instrument [Line Items]
Interest rate margin	0.55%
Revolving Credit Facility \| LIBOR \| Debt Instrument, During, Deferral Period
Debt Instrument [Line Items]
Interest rate margin	2.05%
Revolving Credit Facility \| LIBOR \| Debt Instrument, Following, Deferral Period
Debt Instrument [Line Items]
Interest rate margin	1.55%