Annual report pursuant to Section 13 and 15(d)

Senior Unsecured Notes (Summary Of Senior Unsecured Notes) (Details)

v2.4.1.9
Senior Unsecured Notes (Summary Of Senior Unsecured Notes) (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 12 Months Ended 0 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Dec. 17, 2014
Debt Instrument [Line Items]            
Senior Unsecured Notes $ 1,267,744us-gaap_UnsecuredDebt $ 1,616,575us-gaap_UnsecuredDebt $ 1,267,744us-gaap_UnsecuredDebt $ 1,616,575us-gaap_UnsecuredDebt    
Repayment of senior unsecured notes     350,000us-gaap_RepaymentsOfUnsecuredDebt 100,000us-gaap_RepaymentsOfUnsecuredDebt 221,019us-gaap_RepaymentsOfUnsecuredDebt  
Loss from early extinguishment of debt 582us-gaap_GainsLossesOnExtinguishmentOfDebt 156us-gaap_GainsLossesOnExtinguishmentOfDebt 582us-gaap_GainsLossesOnExtinguishmentOfDebt 156us-gaap_GainsLossesOnExtinguishmentOfDebt 4,960us-gaap_GainsLossesOnExtinguishmentOfDebt  
5.125% Senior Unsecured Notes, Due February 15, 2014 [Member]            
Debt Instrument [Line Items]            
Senior Unsecured Notes    [1] 200,030us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandFourteenMember 		[1]    [1] 200,030us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandFourteenMember 		[1]    
Effective Rate 5.11%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandFourteenMember 		[1],[2]   5.11%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandFourteenMember 		[1],[2]      
Interest rate of senior unsecured notes 5.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandFourteenMember 		  5.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandFourteenMember 		     
Maturity date of the senior unsecured notes     Feb. 15, 2014      
5.125% Senior Unsecured Notes, Due January 15, 2015 [Member]            
Debt Instrument [Line Items]            
Senior Unsecured Notes   149,902us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandFifteenMember 		[3]   149,902us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandFifteenMember 		[3]    
Effective Rate 5.297%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandFifteenMember 		[2],[3]   5.297%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandFifteenMember 		[2],[3]      
Interest rate of senior unsecured notes 5.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandFifteenMember 		  5.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandFifteenMember 		     
Maturity date of the senior unsecured notes     Jan. 15, 2015      
Redemption premium     100.38%cli_SeniorUnsecuredNotesRedemptionPremium
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandFifteenMember 		     
Repayment of senior unsecured notes           153,800us-gaap_RepaymentsOfUnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandFifteenMember
Loss from early extinguishment of debt           600us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointOneTwoFivePercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandFifteenMember
5.800% Senior Unsecured Notes, Due January 15, 2016 [Member]            
Debt Instrument [Line Items]            
Senior Unsecured Notes 200,086us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember 		200,161us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember 		200,086us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember 		200,161us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember 		   
Effective Rate 5.806%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember 		[2]   5.806%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember 		[2]      
Interest rate of senior unsecured notes 5.80%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember 		  5.80%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember 		     
Maturity date of the senior unsecured notes     Jan. 15, 2016      
2.500% Senior Unsecured Notes Due December 15, 2017 [Member]            
Debt Instrument [Line Items]            
Senior Unsecured Notes 249,150us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_TwoPointFiveZeroZeroPercentSeniorUnsecuredNotesDueDecemberFifteenTwoThousandSeventeenMember 		248,855us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_TwoPointFiveZeroZeroPercentSeniorUnsecuredNotesDueDecemberFifteenTwoThousandSeventeenMember 		249,150us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_TwoPointFiveZeroZeroPercentSeniorUnsecuredNotesDueDecemberFifteenTwoThousandSeventeenMember 		248,855us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_TwoPointFiveZeroZeroPercentSeniorUnsecuredNotesDueDecemberFifteenTwoThousandSeventeenMember 		   
Effective Rate 2.803%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_TwoPointFiveZeroZeroPercentSeniorUnsecuredNotesDueDecemberFifteenTwoThousandSeventeenMember 		[2]   2.803%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_TwoPointFiveZeroZeroPercentSeniorUnsecuredNotesDueDecemberFifteenTwoThousandSeventeenMember 		[2]      
Interest rate of senior unsecured notes 2.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_TwoPointFiveZeroZeroPercentSeniorUnsecuredNotesDueDecemberFifteenTwoThousandSeventeenMember 		  2.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_TwoPointFiveZeroZeroPercentSeniorUnsecuredNotesDueDecemberFifteenTwoThousandSeventeenMember 		     
Maturity date of the senior unsecured notes     Dec. 15, 2017      
7.750% Senior Unsecured Notes, Due August 15, 2019 [Member]            
Debt Instrument [Line Items]            
Senior Unsecured Notes 249,013us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_SevenPointSevenFiveZeroPercentSeniorUnsecuredNotesDueAugustFifteenTwoThousandNineteenMember 		248,799us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_SevenPointSevenFiveZeroPercentSeniorUnsecuredNotesDueAugustFifteenTwoThousandNineteenMember 		249,013us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_SevenPointSevenFiveZeroPercentSeniorUnsecuredNotesDueAugustFifteenTwoThousandNineteenMember 		248,799us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_SevenPointSevenFiveZeroPercentSeniorUnsecuredNotesDueAugustFifteenTwoThousandNineteenMember 		   
Effective Rate 8.017%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_SevenPointSevenFiveZeroPercentSeniorUnsecuredNotesDueAugustFifteenTwoThousandNineteenMember 		[2]   8.017%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_SevenPointSevenFiveZeroPercentSeniorUnsecuredNotesDueAugustFifteenTwoThousandNineteenMember 		[2]      
Interest rate of senior unsecured notes 7.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_SevenPointSevenFiveZeroPercentSeniorUnsecuredNotesDueAugustFifteenTwoThousandNineteenMember 		  7.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_SevenPointSevenFiveZeroPercentSeniorUnsecuredNotesDueAugustFifteenTwoThousandNineteenMember 		     
Maturity date of the senior unsecured notes     Aug. 15, 2019      
4.500% Senior Unsecured Notes Due April 18, 2022 [Member]            
Debt Instrument [Line Items]            
Senior Unsecured Notes 299,565us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember 		299,505us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember 		299,565us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember 		299,505us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember 		   
Effective Rate 4.612%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember 		[2]   4.612%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember 		[2]      
Interest rate of senior unsecured notes 4.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember 		  4.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember 		     
Maturity date of the senior unsecured notes     Apr. 18, 2022      
3.150% Senior Unsecured Note, Due May 15, 2023 [Member]            
Debt Instrument [Line Items]            
Senior Unsecured Notes $ 269,930us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember 		$ 269,323us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember 		$ 269,930us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember 		$ 269,323us-gaap_UnsecuredDebt
/ us-gaap_LongtermDebtTypeAxis
= cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember 		   
Effective Rate 3.517%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember 		[2]   3.517%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember 		[2]      
Interest rate of senior unsecured notes 3.15%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember 		  3.15%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember 		     
Maturity date of the senior unsecured notes     May 15, 2023      
[1] On February 17, 2014, the Company repaid these notes at their maturity using available cash and borrowings on the Company’s unsecured revolving credit facility.
[2] Includes the cost of terminated treasury lock agreements (if any), offering and other transaction costs and the discount/premium on the notes, as applicable.
[3] These notes were redeemed on December 17, 2014. The redemption price, including a make-whole premium, was 100.380 percent of the principal amount of the Notes, plus all accrued and unpaid interest up to the Redemption Date. The Company funded the redemption price, including accrued and unpaid interest, of approximately $153.8 million using available cash and borrowings on the Company’s unsecured revolving credit facility. In connection with the redemption, the Company recorded approximately $0.6 million as a loss from early extinguishment of debt (including the write-off of unamortized deferred financing costs).