Name:	cor_DeferredCostsLeasingNetAmortizationExpenseAfterYearFive
Namespace Prefix:	cor_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the amount of amortization expense expected to be recognized during the next fiscal year following the latest fiscal year for deferred leasing costs.

No definition available.

Name:	cor_DeferredCostsLeasingNetAmortizationExpenseNextTwelveMonths
Namespace Prefix:	cor_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the amount of amortization expense expected to be recognized during the fifth fiscal year following the latest fiscal year for deferred leasing costs.

No definition available.

Name:	cor_DeferredCostsLeasingNetAmortizationExpenseYearFive
Namespace Prefix:	cor_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the amount of amortization expense expected to be recognized during the fourth fiscal year following the latest fiscal year for deferred leasing costs.

No definition available.

Name:	cor_DeferredCostsLeasingNetAmortizationExpenseYearFour
Namespace Prefix:	cor_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the amount of amortization expense expected to be recognized during the third fiscal year following the latest fiscal year for deferred leasing costs.

No definition available.

Name:	cor_DeferredCostsLeasingNetAmortizationExpenseYearThree
Namespace Prefix:	cor_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the amount of amortization expense expected to be recognized during the second fiscal year following the latest fiscal year for deferred leasing costs.

No definition available.

Name:	cor_DeferredCostsLeasingNetAmortizationExpenseYearTwo
Namespace Prefix:	cor_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	cor_DeferredCostsLeasingNetFutureAmortizationExpenseAbstract
Namespace Prefix:	cor_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Represents the costs incurred when both (1) the software is acquired, internally developed, or modified solely to meet the entity's internal needs, and (2) during the software's development or modification, no substantive plan exists or is being developed to market the software externally. This element is net of accumulated amortization.

No definition available.

Name:	cor_InternalUseSoftwareNet
Namespace Prefix:	cor_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract
Namespace Prefix:	us-gaap_
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Period Type:	duration

This element represents costs incurred by the lessor that are (a) costs to originate a lease incurred in transactions with independent third parties that (i) result directly from and are essential to acquire that lease and (ii) would not have been incurred had that leasing transaction not occurred and (b) certain costs directly related to specified activities performed by the lessor for that lease. Those activities are: evaluating the prospective lessee's financial condition; evaluating and recording guarantees, collateral, and other security arrangements; negotiating lease terms; preparing and processing lease documents; and closing the transaction. This element is net of accumulated amortization.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 25

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=6748888&loc=d3e40246-112709

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-Name Accounting Standards Codification

-Topic 840

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-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 25

-Paragraph 16

-URI http://asc.fasb.org/extlink&oid=6748888&loc=d3e40588-112709

Name:	us-gaap_DeferredCostsLeasingNet
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Period Type:	instant

For an unclassified balance sheet, the carrying amount (net of accumulated amortization) as of the balance sheet date of capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings over the life of the debt instruments to which such costs pertain.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28555-108399

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

Name:	us-gaap_DeferredFinanceCostsNet
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The cumulative difference between the rental payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other systematic and rational basis more representative of the time pattern in which use or benefit is granted or derived from the leased property, expected to be recognized in income or expense over the term of the leased property, by the lessor or lessee, respectively. Such receivable is reduced by allowances attributable to, for instance, credit risk associated with a lessee.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.8)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 35

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6453741&loc=d3e40879-112712

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-Name Accounting Standards Codification

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-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=7501430&loc=d3e39927-112707

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-Name Accounting Standards Codification

-Topic 840

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-URI http://asc.fasb.org/extlink&oid=7501430&loc=d3e39896-112707

Name:	us-gaap_DeferredRentReceivablesNet
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The aggregate carrying amounts, as of the balance sheet date, of assets not separately disclosed in the balance sheet.

Name:	us-gaap_OtherAssets
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of other miscellaneous assets.

No definition available.

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

Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.13)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 13

-Subparagraph a

-Article 5

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 8

-Article 7