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

- References

No definition available.

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

Repurchase agreement weighted average interest rate held by the entity with maturities within one month.

No definition available.

Name:	chmi_RepurchaseAgreementLessThanOneMonthWeightedAverageRate
Namespace Prefix:	chmi_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Amount of the fixed and determinable portion of the purchase obligation maturing with in one month of the latest fiscal year.

No definition available.

Name:	chmi_RepurchaseAgreementObligationLessThanOneMonthMaturities
Namespace Prefix:	chmi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Repurchase agreement weighted average interest rate held by the entity total.

No definition available.

Name:	chmi_RepurchaseAgreementWeightedAverageRate
Namespace Prefix:	chmi_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Refers to remaining weighted average maturity period of the repurchase agreement, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

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

- References

No definition available.

Name:	srt_BrokersAndDealersAbstract
Namespace Prefix:	srt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount, before effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 210
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483444/210-20-55-22

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 210
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483444/210-20-55-21

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 210
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 20
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483444/210-20-55-20

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 210
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483444/210-20-55-15

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483466/210-20-50-3