Annual report pursuant to Section 13 and 15(d)

Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Schedule Of Stock Option Plans) (Details)

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Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Schedule Of Stock Option Plans) (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Jun. 05, 2015
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]        
Shares Under Options - Granted 800,000      
Outstanding stock option price range, lower range       $ 17.31
Outstanding stock option price range, upper range       $ 21.25
Outstanding stock option price   $ 17.31 $ 17.31  
2013 Incentive Stock Plan [Member]        
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]        
Shares Under Options - Outstanding, beginning balance   800,000 805,000 10,000
Shares Under Options - Granted       800,000
Shares Under Options - Granted, Lapsed or Cancelled      
Shares Under Options - Lapsed or Cancelled     (5,000) (5,000)
Shares Under Options - Outstanding, ending balance   800,000 800,000 805,000
Shares Under Options - Options exercisable   666,666    
Shares Under Options - Available for grant   2,069,064    
Weighted Average Exercise Price - Outstanding, beginning balance   $ 17.31 $ 17.33 $ 33.36
Weighted Average Exercise Price - Granted       17.31
Weighted Average Exercise Price - Granted, Lapsed or Cancelled      
Weighted Average Exercise Price - Lapsed or Cancelled     21.25 45.47
Weighted Average Exercise Price - Outstanding, ending balance   $ 17.31 $ 17.31 $ 17.33
Aggregate Intrinsic Value, Outstanding, beginning balance   $ 9,368 $ 4,843
Aggregate Intrinsic Value, Outstanding, ending balance   $ 3,400 $ 9,368 $ 4,843