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Amount of gross realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

No definition available.

Name:	chmi_DebtSecuritiesAvailableForSaleGrossRealizedLoss
Namespace Prefix:	chmi_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

No definition available.

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

Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-9

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Period Type:	duration

- References

No definition available.

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

Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481830/320-10-45-11

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-9

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-12

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-11