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 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Stockolders Equity [Line Items]        
Basic EPS shares 90,468 90,023 90,355 89,997
Add: Operating Partnership - common and vested LTIP Units 10,244 10,439 10,251 10,394
Restricted Stock Awards   32   37
Stock Options   233 78 273
Diluted EPS Shares 100,712 100,727 100,684 100,701
Mack-Cali Realty LP [Member]        
Stockolders Equity [Line Items]        
Basic EPS units 100,712 100,462 100,606 100,391
Restricted Stock Awards   32   37
Stock Options   233 78 273
Diluted EPU Units 100,712 100,727 100,684 100,701