Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Schedule Of Restricted Stock Awards) (Details)
 12 Months Ended
Dec. 31, 2016
$ / shares
shares
Dec. 31, 2015
$ / shares
item
shares
Dec. 31, 2014
item
$ / shares
shares
Dec. 31, 2013
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares, Outstanding, Beginning balance 136,220 346,946 153,560  
Shares, Granted 74,622 41,337 [1] 376,719 [2],[3],[4]  
Shares, Vested (61,654) (250,132) (183,214)  
Shares, Forfeited (3,910) (1,931) (119)  
Shares, Outstanding, Ending balance 145,278 136,220 346,946 153,560
Weighted-Average Grant-Date Fair Value, Outstanding beginning balance | $ / shares $ 19.36 $ 21.09 $ 25.20  
Weighted-Average Grant-Date Fair Value, Granted | $ / shares 23.79 17.51 [1] 20.04 [2],[3],[4]  
Weighted-Average Grant-Date Fair Value, Vested | $ / shares 18.94 21.44 22.37  
Weighted-Average Grant-Date Fair Value, Forfeited | $ / shares 21.58 20.31 26.36  
Weighted-Average Grant-Date Fair Value, Outstanding ending balance | $ / shares $ 21.76 $ 19.36 $ 21.09 $ 25.20
Unvested performance shares       42,000
Messr Krug And Messr Wagner [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares, Granted     8,211  
Number of executive officers that were granted restricted stock awards | item   2    
Executive Officers [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares, Granted     87,734  
Number of executive officers that were granted restricted stock awards | item   2    
Messr Lefkowitz And Messr Thomas [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of executive officers who departed | item     2  
Messr Rudin And Messr DeMarco [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares, Granted   37,551    
[1] Included in the 41,337 Restricted Stock Awards granted in 2015 were 37,551 awards granted to the Company's two executive officers, Mitchell E. Rudin and Michael J. DeMarco.
[2] Included in the 376,719 Restricted Stock Awards granted in 2014 were 8,211 awards granted to the Company's two executive officers, Anthony Krug and Gary Wagner.
[3] Includes 126,000 Performance Shares which were legally granted in 2013 for which future performance goals had not yet been set by the Committee. These awards were not considered granted for accounting purposes until these goals are set. These were considered granted in 2014 for accounting purposes in connection with the announcement of the departure of Mitchell E. Hersh in the fourth quarter 2014.
[4] Includes 42,000 Performance Shares which were legally granted in 2013 for which the 2014 performance goals were set by the Committee on March 31, 2014. Also includes 87,734 shares which were additionally considered granted for accounting purposes to two executive officers in connection with their departure effective March 31, 2014, which vested on April 1, 2014.