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, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Stockolders Equity [Line Items]        
Basic EPS shares 90,330 90,011 90,297 89,983
Add: Operating Partnership - common and vested LTIP Units 10,268 10,359 10,255 10,371
Stock Options     55  
Diluted EPS Shares 100,598 100,370 100,607 100,354
Mack-Cali Realty LP [Member]        
Stockolders Equity [Line Items]        
Basic EPS units 100,598 100,370 100,552 100,354
Stock Options     55  
Diluted EPU Units 100,598 100,370 100,607 100,354