Name:	cpt_CashRequiredByPlanParticipantsUponWithdrawal
Namespace Prefix:	cpt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Common shares which could be granted pursuant to full value awards based on the 3.45 to 1.0 fungible unit-to-full value award conversion ratio.

No definition available.

Name:	cpt_CommonSharesWhichCouldBeGrantedPursuantToFullValueAwards
Namespace Prefix:	cpt_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Maximum authorized purchase amount of shares during any plan year per participant for our employee share purchase plan.

No definition available.

Name:	cpt_EmployeeSharePurchasePlanMaximumAuthorizedAmountPerParticipant
Namespace Prefix:	cpt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Employee Share Purchase Program maximum shares available under the 2018 ESPP Share plan

No definition available.

Name:	cpt_EmployeeSharePurchaseProgrammaximumsharesavailable
Namespace Prefix:	cpt_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

The full value award in the fungible unit to full value award conversion ratio regarding the shares from the 2002 share incentive plan transferred into the 2011 share incentive plan.

No definition available.

Name:	cpt_FullValueawardinthefungibleunitconversionratio
Namespace Prefix:	cpt_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

The award conversion ratio regarding the shares from the 2002 share incentive plan transferred into the 2011 share incentive plan.

No definition available.

Name:	cpt_FungibleUnitsToFullValueAwardConversionRatio
Namespace Prefix:	cpt_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

The percentage of market value per share at which shares may be purchased under our employee share purchase plan

No definition available.

Name:	cpt_PercentageOfMarketValueatWhichSharesPurchasedUnderEmployeeSharePurchasePlan
Namespace Prefix:	cpt_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The total amount of share awards held in a Rabbi Trust.

No definition available.

Name:	cpt_ShareAwardsHeldInEmployeeTrustShares
Namespace Prefix:	cpt_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

The total amount of share awards held in a non-qualified deferred compensation plan.

No definition available.

Name:	cpt_ShareAwardsHeldInNonQualifiedDeferredCompensationPlanShares
Namespace Prefix:	cpt_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Equity-based compensation cost during the period with respect to the award, which was recognized in income.

No definition available.

Name:	cpt_ShareBasedCompensationArrangementByShareBasedPaymentAwardCompensationCostForPeriod
Namespace Prefix:	cpt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

shares diversified

No definition available.

Name:	cpt_Sharesdiversified
Namespace Prefix:	cpt_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Market value of trading securities held in a rabbi trust.

No definition available.

Name:	cpt_TradingSecuritiesHeldInEmployeeTrustValue
Namespace Prefix:	cpt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Market value of trading securities held in a non-qualified deferred compensation plan.

No definition available.

Name:	cpt_TradingSecuritiesHeldInNonQualifiedDeferredCompensationPlanValue
Namespace Prefix:	cpt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

An option, right, or other award which does not deliver the full value at date of grant and expires five years or less from the date of grant counts against the Fungible Pool Limit as this portion of a fungible pool unit

No definition available.

Name:	cpt_ValueOfOptionRightOrOtherAwardInTheFungibleUnitConversion
Namespace Prefix:	cpt_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

Amount of cost for defined contribution plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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

Amount of cost capitalized for award under share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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

Name:	us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_AwardTypeAxis=cpt_ShareAwardsAndVestingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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