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) (Narrative) (Details)

v3.20.2
Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Restricted Stock Awards And Performance Share Units) (Narrative) (Details) - USD ($)
3 Months Ended 9 Months Ended
Jun. 05, 2018
Jun. 05, 2015
Sep. 30, 2020
Sep. 30, 2020
Jun. 30, 2020
Dec. 31, 2019
Sep. 30, 2019
Jun. 30, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Unvested stock outstanding     52,974 52,974 17,076 42,690 24,200 26,136 67,289
Shares granted     52,974 52,974          
Performance period       3 years          
Restricted Stock [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Unvested stock outstanding     52,974 52,974          
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]                  
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period       1 year          
Restricted Stock [Member] | Maximum [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period       7 years          
Unvested Restricted Stock [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Unvested stock outstanding     52,974 52,974     24,200    
Total Stockholder Return Based Awards [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Total unrecognized compensation cost     $ 600,000 $ 600,000          
Performance Shares [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Unvested performance shares       0          
Total unrecognized compensation cost     $ 0 $ 0          
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] | 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 100.00%                
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%