Number of operating properties acquired which are now fully consolidated during the period.

No definition available.

Name:	cpt_NumberofOperatingpropertiesAcquired
Namespace Prefix:	cpt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Area of land held.

+ References

No definition available.

+ Details

Name:	us-gaap_AreaOfLand
Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount after tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64827811&loc=d3e1361-107760

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3B
-URI http://asc.fasb.org/extlink&oid=65878427&loc=SL51721525-107759

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5C
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721675-107760

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=65878427&loc=d3e957-107759

+ Details

Name:	us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainLossOnSaleOfProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The net gain (loss) resulting from sales and other disposals of real estate owned for investment purposes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.14(d))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

Name:	us-gaap_GainsLossesOnSalesOfInvestmentRealEstate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfRealEstateProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of units in a real estate property owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfUnitsInRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow from the acquisition of real estate intended to generate income for the owner; excludes land acquired for use by the owner.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireLand
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow from the acquisition of a piece of land, anything permanently fixed to it, including buildings, structures on it and so forth; includes real estate intended to generate income for the owner; excludes real estate acquired for use by the owner.

+ References

+ Details

Name:	us-gaap_PaymentsToAcquireRealEstate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from the sale of land held for investment; excludes sales of land held as inventory or productive use.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

+ Details

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

- Definition

The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.

+ References

+ Details

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

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis=cpt_DualPhasePropertySaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis=us-gaap_DiscontinuedOperationsHeldForSaleOrDisposedOfBySaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Acquisitions, Dispositions, Discontinued Operations and Assets Held for Sale (Narrative) (Details) $ in Thousands		1 Months Ended				3 Months Ended			9 Months Ended		12 Months Ended
	Apr. 28, 2017 USD ($) a	Jun. 30, 2017	Sep. 30, 2016 USD ($) a	Apr. 30, 2016 USD ($)	Feb. 29, 2016 USD ($) a	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($) a	Jun. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($) a	Dec. 31, 2016 USD ($)	Jul. 31, 2017	Jun. 01, 2017	Jun. 15, 2016 a	Apr. 26, 2016 a
Number of Operating properties Acquired		1
Area of Land \| a	8.2		2.4		2.0		2.4			2.4				0.2
Payments to Acquire Land	$ 20,000		$ 15,000		$ 4,100		$ 800
Number of Units in Real Estate Property								278				1,005	250
Purchase Price of Operating Properties Acquired									$ 58,267	$ 0
Gain (Loss) on Sale of Properties								$ 32,200
Proceeds from sales of operating properties								$ 39,000
Number of operating properties sold								1				1
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax						$ 0	$ 0		$ 0	$ 375,237	$ 375,200
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Area of Land \| a					6.3
Number of Units in Real Estate Property			2,906				2,906			2,906
Gain (Loss) on Sale of Properties							$ 262,700
Proceeds from sales of operating properties							$ 484,400
Sales price of land					$ 2,200
Gain on sale of land										$ 400
Number of operating properties sold			5				5			5
Dual-Phase Property Sale [Member] \| Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Number of operating properties sold			1				1			1
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Area of Land \| a															19.6
Number of Units in Real Estate Property															4,918
Proceeds from sales of operating properties				$ 630,000
Number of operating properties sold															15