Annual report pursuant to Section 13 and 15(d)

Real Estate Transactions (Summary Of Income From Properties Sold) (Details)

v2.4.1.9
Real Estate Transactions (Summary Of Income From Properties Sold) (Details) (USD $)
 3 Months Ended 12 Months Ended
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]              
Total revenues         $ 33,601,000us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue $ 66,882,000us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue  
Operating and other expenses         (13,454,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense (26,484,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense  
Depreciation and amortization         (8,218,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization (17,765,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization  
Income from properties sold (9,000)us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax 2,157,000us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax 4,530,000us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax 5,133,000us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax 11,811,000us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax 21,878,000us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax  
Impairments (62,153,000)us-gaap_AssetImpairmentCharges [1],[2] (48,700,000)us-gaap_AssetImpairmentCharges [1]     (110,853,000)us-gaap_AssetImpairmentCharges (9,845,000)us-gaap_AssetImpairmentCharges  
Realized gains (losses) on sales, net (1,559,000)us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax [3] 47,321,000us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax 13,758,000us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax   59,520,000us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax (13,175,000)us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax  
Income from properties sold (1,568,000)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax 49,478,000us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax 17,585,000us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax 5,133,000us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax 70,628,000us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax 8,703,000us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax  
Properties Sold, Year To Date [Member]              
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]              
Total revenues         55,677,000us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember 		54,753,000us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember 		28,823,000us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember
Operating and other expenses         (27,993,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember 		(25,142,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember 		(17,248,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember
Depreciation and amortization         (15,061,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember 		(14,522,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember 		(6,371,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortization
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember
Interest income           (615,000)us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestIncome
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember 		4,000us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestIncome
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember
Income from properties sold         12,623,000us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember 		14,474,000us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember 		5,208,000us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember
Impairments         (20,761,000)us-gaap_AssetImpairmentCharges
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember 		   
Realized gains (losses) on sales, net             54,848,000us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember
Income from properties sold         $ (8,138,000)us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember 		$ 14,474,000us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember 		$ 60,056,000us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax
/ us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis
= cli_PropertiesSoldYearToDateMember
[1] Amounts for the year ended December 31, 2013 relate to impairment charges as further described in Note 3: Real Estate Transactions - Impairments on Properties Held and Used.
[2] During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,260,000 to correct an error in the measurement of its impairment charges on certain properties in the third quarter of 2013. In the third quarter, in measuring the impairments on these properties, the Company did not include certain tenant improvement amounts to be paid for in-place leases in its discounted cash flows used to measure fair value and, as a result, should have recognized larger impairment charges by this aggregate amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.
[3] During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,559,000 to correct an error in its calculation of the gain on sale of rental property on a transaction that closed in the third quarter of 2013. In the third quarter, in recording the gain on the sale transaction, the Company did not include the full consolidated carrying amount of the property in computing the gain and, as a result, should have recognized a smaller gain by this amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.