Quarterly report pursuant to Section 13 or 15(d)

Mortgages, Loans Payable And Other Obligations (Summary Of Mortgages, Loans Payable And Other Obligations) (Details)

v2.4.1.9
Mortgages, Loans Payable And Other Obligations (Summary Of Mortgages, Loans Payable And Other Obligations) (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Debt Instrument [Line Items]    
Mortgages, loans payable and other obligations $ 797,554us-gaap_SecuredDebt $ 820,910us-gaap_SecuredDebt
Overlook - Site IIID, IIIC, IIIA [Member]    
Debt Instrument [Line Items]    
Property Name Overlook - Site IIID,IIIC, IIIA (b) [1]  
Lender Wells Fargo Bank N.A. [1]  
LIBOR LIBOR+3.50 [1],[2]  
Property Debt, Interest Rate, Spread Over LIBOR 3.50%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= cli_OverlookSiteIIIDIIICIIIMember 		 
Mortgages, loans payable and other obligations    [1] 17,260us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_OverlookSiteIIIDIIICIIIMember 		[1]
Overlook - Site IIB [Member]    
Debt Instrument [Line Items]    
Property Name Overlook - Site IIB (Quarrystone I) (b) [1]  
Lender Wells Fargo Bank N.A. [1]  
LIBOR LIBOR+2.50 [1],[2]  
Property Debt, Interest Rate, Spread Over LIBOR 2.50%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= cli_OverlookSiteIIIBMember 		 
Mortgages, loans payable and other obligations    [1] 5,787us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_OverlookSiteIIIBMember 		[1]
6 Becker, 85 Livingston, 75 Livingston & 20 Waterview [Member]    
Debt Instrument [Line Items]    
Property Name 6 Becker, 85 Livingston, 75 Livingston & 20 Waterview [3]  
Lender Wells Fargo CMBS [3]  
Effective Rate 10.26%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_SixBeckerEightyFiveLivingstonSeventyFiveLivingstonAndTwentyWaterviewMember 		[2],[3]  
Mortgages, loans payable and other obligations 65,035us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_SixBeckerEightyFiveLivingstonSeventyFiveLivingstonAndTwentyWaterviewMember 		[3] 65,035us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_SixBeckerEightyFiveLivingstonSeventyFiveLivingstonAndTwentyWaterviewMember 		[3]
Maturity Aug. 11, 2014 [3],[4]  
Number of properties used to collateralized mortgage 4cli_NumberOfPropertiesUsedToCollateralizeMortgage
/ us-gaap_DebtInstrumentAxis
= cli_SixBeckerEightyFiveLivingstonSeventyFiveLivingstonAndTwentyWaterviewMember 		 
4 Sylvan [Member]    
Debt Instrument [Line Items]    
Property Name 4 Sylvan  
Lender Wells Fargo CMBS  
Effective Rate 10.26%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_FourSylvanMember 		[2]  
Mortgages, loans payable and other obligations 14,575us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_FourSylvanMember 		14,575us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_FourSylvanMember
Maturity Aug. 11, 2014 [4]  
10 Independence [Member]    
Debt Instrument [Line Items]    
Property Name 10 Independence  
Lender Wells Fargo CMBS  
Effective Rate 10.26%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_TenIndependenceMember 		[2]  
Mortgages, loans payable and other obligations 16,924us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_TenIndependenceMember 		16,924us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_TenIndependenceMember
Maturity Aug. 11, 2014 [4]  
9200 Edmonston Road [Member]    
Debt Instrument [Line Items]    
Property Name 9200 Edmonston Road (e) [5]  
Lender Principal Commercial Funding L.L.C. [5]  
Effective Rate 5.534%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_NineThousandTwoHundredEdmonstonRoadMember 		[2],[5]  
Mortgages, loans payable and other obligations 3,903us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_NineThousandTwoHundredEdmonstonRoadMember 		[5] 3,951us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_NineThousandTwoHundredEdmonstonRoadMember 		[5]
Maturity May 01, 2015 [5]  
Port Imperial South [Member]    
Debt Instrument [Line Items]    
Property Name Port Imperial South  
Lender Wells Fargo Bank N.A.  
LIBOR LIBOR+1.75 [2]  
Property Debt, Interest Rate, Spread Over LIBOR 1.75%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= cli_PortImperialSouthMember 		 
Mortgages, loans payable and other obligations 44,333us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_PortImperialSouthMember 		44,119us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_PortImperialSouthMember
Maturity Sep. 19, 2015  
4 Becker [Member]    
Debt Instrument [Line Items]    
Property Name 4 Becker  
Lender Wells Fargo CMBS  
Effective Rate 9.55%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_FourBeckerMember 		[2]  
Mortgages, loans payable and other obligations 39,568us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_FourBeckerMember 		39,421us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_FourBeckerMember
Maturity May 11, 2016  
5 Becker [Member]    
Debt Instrument [Line Items]    
Property Name 5 Becker (f) [6]  
Lender Wells Fargo CMBS [6]  
Effective Rate 19.45%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_FiveBeckerMember 		[2],[6]  
Mortgages, loans payable and other obligations 14,073us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_FiveBeckerMember 		[6] 13,867us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_FiveBeckerMember 		[6]
Maturity May 11, 2016 [6]  
210 Clay [Member]    
Debt Instrument [Line Items]    
Property Name 210 Clay (g) [7]  
Lender Wells Fargo CMBS [7]  
Effective Rate 18.10%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_TwoHundredTenClayMember 		[2],[7]  
Mortgages, loans payable and other obligations 13,549us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_TwoHundredTenClayMember 		[7] 13,330us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_TwoHundredTenClayMember 		[7]
Maturity May 11, 2016 [7]  
Curtis Center [Member]    
Debt Instrument [Line Items]    
Property Name Curtis Center (h) [8]  
Lender CCRE & PREFG [8]  
LIBOR LIBOR+5.912 [2],[8],[9]  
Property Debt, Interest Rate, Spread Over LIBOR 5.912%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember 		 
Mortgages, loans payable and other obligations 64,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember 		[8] 64,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember 		[8]
Maturity Oct. 09, 2016 [8]  
Percentage of interest in venture 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember 		 
Number of extension options 3cli_DebtInstrumentNumberOfExtensionOptions
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember 		 
Loan extension period 1 year  
Deferred financing costs amortization interest rate 1.362%cli_DebtInstrumentDeferredFinancingCostsAmortizationInterestRate
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember 		 
Curtis Center [Member] | Senior Loan [Member]    
Debt Instrument [Line Items]    
Effective Rate 3.469%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		 
Property Debt, Interest Rate, Spread Over LIBOR 3.29%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		 
Mortgages, loans payable and other obligations 102,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		 
Percentage of interest in loan 50.00%cli_PercentageOfInterestInLoan
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember 		 
LIBOR measurement period 1 month  
Curtis Center [Member] | Mezzanine Loan [Member]    
Debt Instrument [Line Items]    
Effective Rate 9.675%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember
/ us-gaap_LongtermDebtTypeAxis
= cli_MezzanineLoanMember 		 
Property Debt, Interest Rate, Spread Over LIBOR 9.50%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember
/ us-gaap_LongtermDebtTypeAxis
= cli_MezzanineLoanMember 		 
Mortgages, loans payable and other obligations 26,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember
/ us-gaap_LongtermDebtTypeAxis
= cli_MezzanineLoanMember 		 
Percentage of interest in loan 50.00%cli_PercentageOfInterestInLoan
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember
/ us-gaap_LongtermDebtTypeAxis
= cli_MezzanineLoanMember 		 
Maximum borrowing capacity 48,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= cli_CurtisCenterMember
/ us-gaap_LongtermDebtTypeAxis
= cli_MezzanineLoanMember 		 
LIBOR measurement period 1 month  
Various [Member]    
Debt Instrument [Line Items]    
Property Name Various (i) [10]  
Lender Prudential Insurance [10]  
Effective Rate 6.332%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_VariousMember 		[10],[2]  
Mortgages, loans payable and other obligations 145,058us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_VariousMember 		[10] 145,557us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_VariousMember 		[10]
Maturity Jan. 15, 2017 [10]  
Number of properties used to collateralized mortgage 7cli_NumberOfPropertiesUsedToCollateralizeMortgage
/ us-gaap_DebtInstrumentAxis
= cli_VariousMember 		 
150 Main St [Member]    
Debt Instrument [Line Items]    
Property Name 150 Main St.  
Lender Webster Bank  
LIBOR LIBOR+2.35 [2]  
Property Debt, Interest Rate, Spread Over LIBOR 2.35%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= cli_OneHundredFiftyMainStreetMember 		 
Mortgages, loans payable and other obligations 1,963us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_OneHundredFiftyMainStreetMember 		1,193us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_OneHundredFiftyMainStreetMember 		[11]
Maturity Mar. 30, 2017  
Maximum borrowing capacity 28,800us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= cli_OneHundredFiftyMainStreetMember 		 
23 Main Street [Member]    
Debt Instrument [Line Items]    
Property Name 23 Main Street  
Lender JPMorgan CMBS  
Effective Rate 5.587%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_TwentyThreeMainStreetMember 		[2]  
Mortgages, loans payable and other obligations 29,041us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_TwentyThreeMainStreetMember 		29,210us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_TwentyThreeMainStreetMember
Maturity Sep. 01, 2018  
Harborside Plaza 5 [Member]    
Debt Instrument [Line Items]    
Property Name Harborside Plaza 5  
Lender The Northwestern Mutual Life Insurance Co. & New York Life Insurance Co.  
Effective Rate 6.842%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_HarborsidePlazaFiveMember 		[2]  
Mortgages, loans payable and other obligations 220,630us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_HarborsidePlazaFiveMember 		221,563us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_HarborsidePlazaFiveMember
Maturity Nov. 01, 2018  
100 Walnut Avenue [Member]    
Debt Instrument [Line Items]    
Property Name 100 Walnut Avenue  
Lender Guardian Life Insurance Co.  
Effective Rate 7.311%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_OneHundredWalnutAvenueMember 		[2]  
Mortgages, loans payable and other obligations 18,476us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_OneHundredWalnutAvenueMember 		18,542us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_OneHundredWalnutAvenueMember
Maturity Feb. 01, 2019  
One River Center [Member]    
Debt Instrument [Line Items]    
Property Name One River Center (j) [12]  
Lender Guardian Life Insurance Co. [12]  
Effective Rate 7.311%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_OneRiverCenterMember 		[12],[2]  
Mortgages, loans payable and other obligations 42,326us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_OneRiverCenterMember 		[12] 42,476us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_OneRiverCenterMember 		[12]
Maturity Feb. 01, 2019 [12]  
Number of properties used to collateralized mortgage 3cli_NumberOfPropertiesUsedToCollateralizeMortgage
/ us-gaap_DebtInstrumentAxis
= cli_OneRiverCenterMember 		 
Park Square [Member]    
Debt Instrument [Line Items]    
Property Name Park Square  
Lender Wells Fargo Bank N.A.  
LIBOR LIBOR+1.872 [13],[2]  
Property Debt, Interest Rate, Spread Over LIBOR 1.872%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= cli_ParkSquareMember 		 
Mortgages, loans payable and other obligations 27,500us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_ParkSquareMember 		27,500us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_ParkSquareMember
Maturity Apr. 10, 2019  
Deferred financing costs amortization interest rate 0.122%cli_DebtInstrumentDeferredFinancingCostsAmortizationInterestRate
/ us-gaap_DebtInstrumentAxis
= cli_ParkSquareMember 		 
Port Imperial South 4/5 Retail [Member]    
Debt Instrument [Line Items]    
Property Name Port Imperial South 4/5 Retail  
Lender American General Life & A/G PC  
Effective Rate 4.559%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_PortImperialFourAndFiveRetailMember 		[2]  
Mortgages, loans payable and other obligations 4,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_PortImperialFourAndFiveRetailMember 		4,000us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_PortImperialFourAndFiveRetailMember
Maturity Dec. 01, 2021  
Port Imperial South 4/5 Garage [Member]    
Debt Instrument [Line Items]    
Property Name Port Imperial South 4/5 Garage  
Lender American General Life & A/G PC  
Effective Rate 4.853%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= cli_PortImperialFourAndFiveGarageDevelopmentMember 		[2]  
Mortgages, loans payable and other obligations $ 32,600us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_PortImperialFourAndFiveGarageDevelopmentMember 		$ 32,600us-gaap_SecuredDebt
/ us-gaap_DebtInstrumentAxis
= cli_PortImperialFourAndFiveGarageDevelopmentMember
Maturity Dec. 01, 2029  
[1] On March 27, 2015, the Company repaid these loans at par, using borrowings on the Company's unsecured revolving credit facility.
[2] Reflects effective rate of debt, including deferred financing costs, comprised of the cost of terminated treasury lock agreements (if any), debt initiation costs, mark-to-market adjustment of acquired debt and other transaction costs, as applicable.
[3] Mortgage is cross collateralized by the four properties.
[4] The loan was not repaid at maturity and the Company has begun discussions with the lender regarding a potential deed-in-lieu of foreclosure in satisfaction of the obligation.
[5] The mortgage loan originally matured on May 1, 2013. The maturity date was extended until May 1, 2015 with the same interest rate. Excess cash flow, as defined, is being held by the lender for re-leasing costs. The deed for the property was placed in escrow and is available to the lender in the event of default or non-payment at maturity.
[6] The cash flow from this property is insufficient to cover operating costs and debt service. Consequently, the Company notified the lender and suspended debt service payments in August 2013. The Company has begun discussions with the lender regarding a deed-in-lieu of foreclosure and began remitting available cash flow to the lender effective August 2013.
[7] The cash flow from this property is insufficient to cover operating costs and debt service. Consequently, the Company notified the lender and suspended debt service payments in January 2015.
[8] The Company owns a 50 percent tenants-in-common interest in the Curtis Center property. The Company’s $64.0 million loan consists of its 50 percent interest in a $102 million senior loan with a current rate of 3.469 percent at March 31, 2015 and its 50 percent interest in a $26 million mezzanine loan (with a maximum borrowing capacity of $48 million) with a current rate of 9.675 percent at March 31, 2015. The senior loan rate is based on a floating rate of one-month LIBOR plus 329 basis points and the mezzanine loan rate is based on a floating rate of one-month LIBOR plus 950 basis points. The Company has entered into LIBOR caps for the periods of the loans. The loans provide for three one-year extension options.
[9] The effective interest rate includes amortization of deferred financing costs of 1.362 percent.
[10] Mortgage is cross collateralized by seven properties. The Company has agreed, subject to certain conditions, to guarantee repayment of a portion of the loan.
[11] This construction loan has a maximum borrowing capacity of $28.8 million.
[12] Mortgage is collateralized by the three properties comprising One River Center.
[13] The effective interest rate includes amortization of deferred financing costs of 0.122 percent.