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
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Stockolders Equity [Line Items]      
Basic EPS shares 90,005 89,746 89,291
Add: Operating Partnership - common units 10,405 10,499 10,931
Restricted Stock Awards 40 43  
Stock Options 253 210  
Diluted EPS Shares 100,703 100,498 100,222
Mack-Cali Realty LP [Member]      
Stockolders Equity [Line Items]      
Basic weighted average units outstanding 100,410 100,245 100,222
Restricted Stock Awards 40 43  
Stock Options 253 210  
Diluted weighted average units outstanding 100,703 100,498 100,222