Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Schedule Of Reconciliation Of Shares Used In Basic EPS Calculation To Shares Used In Diluted EPS Calculation) (Details) - shares
shares in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Stockolders Equity [Line Items]        
Basic EPS shares 90,533 90,330 90,516 90,297
Add: Operating Partnership - common and vested LTIP units 9,990 10,268 10,115 10,255
Restricted Stock Awards     26  
Stock Options     168 55
Diluted EPS Shares 100,523 100,598 100,825 100,607
Mack-Cali Realty LP [Member]        
Stockolders Equity [Line Items]        
Basic EPS units 100,523 100,598 100,631 100,552
Restricted Stock Awards     26  
Stock Options     168 55
Diluted EPU Units 100,523 100,598 100,825 100,607