COMPENSATION PROGRAMS - Defined Contribution Plans (Details) (USD $)	12 Months Ended
Dec. 31, 2013
Defined Contribution Plan Disclosure [Abstract]
Defined contribution plan voluntary contribution based on compensation (in hundredths)	50.00%
Defined contribution plan, maximum annual contributions per employee (in hundredths)	6.00%
Defined contribution plan, employer matching contribution (in hundredths)	3.00%
Defined contribution plan, cost recognized	$ 320,000

The percentage of a participant's voluntary contribution the Company will match.

No definition available.

Name:	cmo_CompensationPlanOfVoluntaryContribution
Namespace Prefix:	cmo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

+ Details

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

- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration