Other Assets (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Other Assets
Deferred leasing costs	$ 27,710us-gaap_DeferredCostsLeasingNet	$ 27,229us-gaap_DeferredCostsLeasingNet
Deferred rent receivable	22,091us-gaap_DeferredRentReceivablesNet	21,510us-gaap_DeferredRentReceivablesNet
Corporate furniture, fixtures and equipment	8,048us-gaap_PropertyPlantAndEquipmentNet	7,980us-gaap_PropertyPlantAndEquipmentNet
Internal-use software	2,127cor_InternalUseSoftwareNet	2,421cor_InternalUseSoftwareNet
Deferred financing costs	7,181us-gaap_DeferredFinanceCostsNet	7,474us-gaap_DeferredFinanceCostsNet
Other	6,615us-gaap_OtherAssetsMiscellaneous	8,986us-gaap_OtherAssetsMiscellaneous
Total	73,772us-gaap_OtherAssets	75,600us-gaap_OtherAssets
Estimated amortization of deferred leasing costs
Total	$ 27,710us-gaap_DeferredCostsLeasingNet	$ 27,229us-gaap_DeferredCostsLeasingNet

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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.

+ References

No definition available.

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- Definition

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.

+ References

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

-Publisher FASB

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- Definition

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.

+ References

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

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- Definition

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.

+ References

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+ Details

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- Definition

The aggregate carrying amounts, as of the balance sheet date, of assets not separately disclosed in the balance sheet.

+ References

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- Definition

Amount of other miscellaneous assets.

+ References

No definition available.

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- Definition

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.

+ References

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