Refers to the unpaid principal balance on mortgage servicing rights loans.

No definition available.

Name:	chmi_AggregateUnpaidPrincipalBalanceOnMortgageServicingRights
Namespace Prefix:	chmi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount of compensation reimbursement on expenses incurred.

+ References

No definition available.

+ Details

Name:	chmi_CompensationReimbursement
Namespace Prefix:	chmi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Term of the management arrangement renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	chmi_ManagementAgreementRenewalPeriod
Namespace Prefix:	chmi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of the notice for management arrangement non-renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	chmi_ManagementAgreementSubjectToNonRenewalPeriodOfNotice
Namespace Prefix:	chmi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of the notice to manager for termination of management arrangement renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	chmi_ManagementAgreementSubjectToTerminationNoticePeriodForTerminationToManager
Namespace Prefix:	chmi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of the notice of termination of agreement by the manager to entity in the event of default, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	chmi_ManagementAgreementSubjectToTerminationPeriodOfNoticeByManagerInTheEventOfDefault
Namespace Prefix:	chmi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of termination fee payment by the manager to entity in the event of default, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	chmi_ManagementAgreementSubjectToTerminationPeriodOfTerminationFeePaymentInTheEventOfDefault
Namespace Prefix:	chmi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of management fee and expense reimbursement to affiliate.

+ References

No definition available.

+ Details

Name:	chmi_ManagementFeeAndExpenseReimbursementToAffiliate
Namespace Prefix:	chmi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	chmi_ManagementFeesAndCompensationReimbursementToAffiliateAbstract
Namespace Prefix:	chmi_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of employees leases from the mortgage.

+ References

No definition available.

+ Details

Name:	chmi_NumberOfEmployeesLeasesFromMortgage
Namespace Prefix:	chmi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow associated with the acquisition of payments to acquire MSRs.

+ References

No definition available.

+ Details

Name:	chmi_PaymentsToAcquireMortgageServicingRights
Namespace Prefix:	chmi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of annual management fee paid equal to gross equity.

+ References

No definition available.

+ Details

Name:	chmi_PercentageOfGrossEquityPaidToManagerAsAnnualManagementFee
Namespace Prefix:	chmi_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	chmi_RelatedPartyDisclosureAbstract
Namespace Prefix:	chmi_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of servicing fees receivable.

+ References

No definition available.

+ Details

Name:	chmi_ServicingReceivables
Namespace Prefix:	chmi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Refers to the additional term of subservicing agreements after renewal, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	chmi_SubservicingOfFinancialAssetsAgreementsAdditionalTerm
Namespace Prefix:	chmi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2(a),(d))
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

+ Details

Name:	us-gaap_CostOfGoodsAndServicesSold
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of expenses related to the managing member or general partner for management of the day-to-day business functions of the limited liability company (LLC) or limited partnership (LP).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

+ Details

Name:	us-gaap_ManagementFeeExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=chmi_RoundPointMortgageServicingCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_InvestmentTypeAxis=chmi_MortgageServiceRightMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=chmi_FlowAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=chmi_FreedomMortgageExcessServiceRightMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Transactions with Related Parties (Details)	3 Months Ended
Transactions with Related Parties (Details)	Mar. 31, 2022 USD ($) Employee	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Related Party Transactions [Abstract]
Percentage of annual management fee paid equal to gross equity	1.50%
Renew of management agreement subject to termination	1 year
Management agreement subject to termination, notice period for termination to manager	30 days
Management agreement subject to termination, period of notice by manager in the event of default	60 days
Management agreement subject to termination, period of termination fee payment in the event of default	30 days
Servicing costs	$ 3,193,000	$ 3,082,000
Agreement purchase price	5,645,000	20,295,000
Management Fees and Compensation Reimbursement to Affiliate [Abstract]
Management fees	1,678,000	1,711,000
Compensation reimbursement	115,000	250,000
Total	$ 1,793,000	1,961,000
Minimum [Member]
Related Party Transactions [Abstract]
Management agreement subject to non-renewal, notice period	180 days
Maximum [Member]
Related Party Transactions [Abstract]
Management agreement subject to non-renewal, notice period	270 days
RoundPoint Mortgage Servicing Corporation [Member]
Related Party Transactions [Abstract]
Subservicing agreement term	2 years
Aurora Financial Group, Inc. [Member] \| RoundPoint Mortgage Servicing Corporation [Member]
Related Party Transactions [Abstract]
Servicing costs	$ 1,700,000	1,300,000
Servicing receivables	4,100,000		$ 493,000
Mortgage Servicing Rights (MSRs) [Member] \| Aurora Financial Group, Inc. [Member] \| RoundPoint Mortgage Servicing Corporation [Member] \| Flow Agreement [Member]
Related Party Transactions [Abstract]
Aggregate unpaid principal balance	57,000,000.0	1,800,000,000
Agreement purchase price	$ 650,000	$ 14,000,000.0
Freedom Mortgage Excess Service Right [Member]
Related Party Transactions [Abstract]
Number of employees leases from mortgage \| Employee	3