Document And Entity Information (USD $)
 12 Months Ended
Dec. 31, 2011
Feb. 06, 2012
Jun. 30, 2011
Document And Entity Information [Abstract]      
Entity Registrant Name MACK CALI REALTY CORP    
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2011    
Entity Central Index Key 0000924901    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Entity Common Stock, Shares Outstanding   87,800,496  
Document Fiscal Year Focus 2011    
Document Fiscal Period Focus FY    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Well-known Seasoned Issuer Yes    
Entity Public Float     $ 2,828,296,158