Document And Entity Information - shares
 9 Months Ended
Sep. 30, 2018
Oct. 29, 2018
Entity Registrant Name MACK CALI REALTY CORP  
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2018  
Entity Central Index Key 0000924901  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Entity Common Stock, Shares Outstanding   90,320,226
Entity Emerging Growth Company false  
Entity Small Business false  
Mack-Cali Realty LP [Member]    
Entity Registrant Name Mack Cali Realty LP  
Entity Central Index Key 0001067063  
Entity Filer Category Large Accelerated Filer