Quarterly report pursuant to Section 13 or 15(d)

Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Restricted Stock Awards And Performance Share Units/TSR-Based Awards) (Narrative) (Details)

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Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Restricted Stock Awards And Performance Share Units/TSR-Based Awards) (Narrative) (Details) - USD ($)
$ in Millions
9 Months Ended
Jun. 05, 2015
Sep. 30, 2016
Dec. 31, 2015
Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unvested restricted stock outstanding   107,749 136,220  
Shares granted   36,870    
Shares issued   4,299,000    
Restricted Stock [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unvested restricted stock outstanding   82,716    
Restricted Stock [Member] | 2013 Incentive Stock Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares granted 37,550.54      
Performance period   3 years    
Restricted Stock [Member] | Minimum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock compensation vesting period   1 year    
Restricted Stock [Member] | Maximum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock compensation vesting period   7 years    
Unvested Restricted Stock [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unvested restricted stock outstanding   82,716   99,006
Total Stockholder Return Based Awards [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total unrecognized compensation cost   $ 0.5    
Total unrecognized compensation cost, period of recognition   6 months    
Performance Shares [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total unrecognized compensation cost   $ 0.8    
Total unrecognized compensation cost, period of recognition   1 year 8 months 12 days    
Performance Shares [Member] | 2013 Incentive Stock Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares granted 112,651.64      
Performance period   3 years    
Performance Shares [Member] | Minimum [Member] | 2013 Incentive Stock Plan [Member] | Three Years Period Award [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Percentage of shares vested 0.00%      
Performance Shares [Member] | Maximum [Member] | 2013 Incentive Stock Plan [Member] | Three Years Period Award [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Percentage of shares vested 150.00%