Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Deferred Stock Compensation Plan For Directors) (Narrative) (Details) - shares
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital [Abstract]      
Maximum percentage of retainer fee that directors may defer 100.00%    
Deferred stock units earned 7,420 4,265  
Deferred stock units outstanding 216,465   210,738