Quarterly report pursuant to Section 13 or 15(d)

Mack-Cali Realty Corporation Stockholders' Equity (Stock Options Plans) (Narrative) (Details)

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Mack-Cali Realty Corporation Stockholders' Equity (Stock Options Plans) (Narrative) (Details)
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 05, 2015
item
$ / shares
shares
Jun. 30, 2016
USD ($)
shares
Jun. 30, 2015
USD ($)
Jun. 30, 2016
USD ($)
shares
Jun. 30, 2015
USD ($)
shares
Dec. 31, 2015
May 31, 2013
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock option terms       10 years      
Weighted average remaining contractual life       8 years 10 months 24 days   9 years 4 months 24 days  
Share price | $ / shares $ 17.31            
Options exercised       0 0    
Stock options expense | $   $ 183,000 $ 62,000 $ 367,000 $ 63,000    
Shares Under Options - Granted 800,000            
Common stock trade share price | $ / shares $ 25.00            
Annual installments | item 3            
Exercisable period       10 years      
Common stock trading days       30 days      
Three Equal Annual Installment [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Shares Under Options - Granted 400,000            
Common Stock Trades [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Shares Under Options - Granted 400,000            
2013 Incentive Stock Plan [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Reserved stocks for issuance             4,600,000
Employee And Director Plan [Member] | Minimum [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Reserved stocks for issuance   2,700,000   2,700,000      
Employee And Director Plan [Member] | Maximum [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Reserved stocks for issuance   4,350,000   4,350,000      
2000 Employee Plan [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Exercisable time period       5 years      
2000 Employee Plan [Member] | Minimum [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Reserved stocks for issuance   2,500,000   2,500,000      
2000 Employee Plan [Member] | Maximum [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Reserved stocks for issuance   4,000,000   4,000,000      
2000 Director Plan [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Exercisable time period       1 year      
2000 Director Plan [Member] | Minimum [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Reserved stocks for issuance   200,000   200,000      
2000 Director Plan [Member] | Maximum [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Reserved stocks for issuance   350,000   350,000