Authorized percentage of contributions to savings plan by participant.

No definition available.

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

- Definition

Cash required to be paid to us by plan participants upon the withdrawal of any assets from the trust and is included in accounts receivable - affiliates in our consolidated financial statements.

+ References

No definition available.

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Shares reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable, specifically for the 2011 Share Plan, which superseded the 2002 Share Plan.

+ References

No definition available.

+ Details

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

- Definition

Shares reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable, specifically from the 2002 Share Plan, which has been superseded by the 2011 Share Plan.

+ References

No definition available.

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage increase in options exercisable per year due to vesting of the options on the each of the anniversaries of the date of grant.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Percentage of participant's salary deferral contribution matching by the company that will be vested after one year.

+ References

No definition available.

+ Details

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

- Definition

Percentage of participant's salary deferral contribution matching by the company that will be vested after three years.

+ References

No definition available.

+ Details

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

- Definition

Percentage of participant's salary deferral contribution matching by the company that will be vested after two years.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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Namespace Prefix:	cpt_
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Balance Type:	na
Period Type:	instant

- Definition

Market value of trading securities held in a rabbi trust.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Exercise price of the option.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

+ Details

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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 Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 11

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-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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Balance Type:	debit
Period Type:	duration

- Definition

Represents the compensation cost capitalized during the period arising from equity-based compensation arrangements (for example, shares of stock, units, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph g(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-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=6415400&loc=d3e5070-113901

+ Details

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Period Type:	duration

- Definition

As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph h

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

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Period Type:	instant

- Definition

The weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, using a decimal to express in number of years.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph h

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

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- Definition

Description of the period of time over which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, which may be expressed in a variety of ways (for example, in years, month and year).

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

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Period Type:	duration

- Definition

The maximum vesting term over which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition.

+ References

No definition available.

+ Details

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Data Type:	us-types:dateStringItemType
Balance Type:	na
Period Type:	duration

- Definition

The minimum vesting term over which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Equity-based compensation cost during the period with respect to the award, which will be recognized in income (as well as the total recognized tax benefit) or capitalized as part of the cost of an asset.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 50

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(1)

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64, 65

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph g(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

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Balance Type:	debit
Period Type:	duration

- Definition

The total fair value of equity-based awards for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph c(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (d)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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- Definition

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.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Balance Type:	na
Period Type:	instant

- Definition

The weighted average period between the balance sheet date and expiration for all vested portions of options outstanding and currently exercisable (or convertible) under the plan, which may be expressed in a decimal value for number of years.

+ References

+ Details

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Period Type:	duration

- Definition

The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) into shares during the reporting period under the plan.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph c(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (d)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Period Type:	duration

- Definition

The weighted average period between the balance sheet date and expiration for all awards outstanding under the plan, which may be expressed in a decimal value for number of years.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Section 50

-Paragraph 2

-Subparagraph (e)(1)

-SubTopic 10

-Topic 718

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Balance Type:	na
Period Type:	instant

- Definition

Number of shares issued during the period as a result of an employee stock purchase plan.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

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-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 12

-Paragraph 10

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

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-Name Regulation S-X (SX)

-Number 210

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-Article 3

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-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 5

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

Number of share options (or share units) exercised during the current period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

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-Paragraph 2

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-Name Accounting Standards Codification

-Topic 210

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-Name Regulation S-X (SX)

-Number 210

-Section 04

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-Name Accounting Standards Codification

-Topic 718

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-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

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-Name Accounting Standards Codification

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-Paragraph 1

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Share-Based Compensation And Benefit Plans (Narrative) (Details) (USD $)	1 Months Ended	12 Months Ended
	Jan. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based payment awards, shares available for grant		2,600,000
Common share options exercised		504,838	141,213	18,521
Total intrinsic value of options exercised		$ 9,600,000	$ 1,500,000	$ 100,000
Vesting period of options, minimum, years		three
Vesting period of options, maximum, years		five
Share awards vesting period, years		five
Remaining weighted average contractual life (years) outstanding options		4.7
Remaining weighted average contractual life (years) exercisable options		3.5
Fair value of shares vested		11,500,000	10,600,000	10,200,000
Total compensation cost for option and share awards		12,300,000	11,700,000	8,700,000
Total capitalized compensation cost for option and share awards		900,000	1,000,000	1,700,000
Percentage of market value, shares purchase price under ESPP		85.00%
Employee share purchase plan, maximum authorized amount		25,000
Shares purchased under ESPP	4,721	19,914	29,100	34,649
Share awards held in trust		2,000,000	2,000,000
Share awards held in non-qualified deferred compensation plan shares		900,000	700,000
Market value of trading securities held in non-qualified deferred compensation plan		14,500,000	14,300,000
Market value of trading securities held in Rabbi Trust		45,200,000	53,100,000
Percentage of company's matching contribution vested after one year		33.00%
Percentage of company's matching contribution vested after two years		67.00%
Percentage of company's matching contribution vested after three years		100.00%
2011 Share Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares which could be granted pursuant to full value awards		2,600,000
Share-based payment awards, shares available for grant		9,100,000
Units available under the 2011 Share Plan		5,800,000
Fungible units transferred from the 2002 Share Plan to the 2011 Share Plan		3,300,000
Fungible units to full value award conversion ratio		3.45
Expiration value of option right or other award		0.83
Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to unvested options which is expected to be amortized		1,300,000
Expected amortized period of unrecognized compensation expected to be recognized for share-based compensation plans, years		3
Share Awards and Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to unvested options which is expected to be amortized		27,300,000
Expected amortized period of unrecognized compensation expected to be recognized for share-based compensation plans, years		4
Rabbi Trust [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Receivables from participants upon withdrawal		28,700,000	31,400,000
401(K) Savings Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Matching contribution made to savings plan		$ 1,800,000	$ 1,300,000	$ 1,300,000
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price range for options exercised during the period		$ 30.06
Percentage increase in options exercisable per year		20.00%
Authorized percentage of contributions to savings plan by participant		1.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price range for options exercised during the period		$ 62.32
Percentage increase in options exercisable per year		33.33%
Authorized percentage of contributions to savings plan by participant		60.00%