Annual report pursuant to Section 13 and 15(d)

Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Restricted Stock Awards) (Narrative) (Details)

v3.20.4
Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Restricted Stock Awards) (Narrative) (Details) - USD ($)
$ in Millions
12 Months Ended
Jun. 05, 2015
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Unvested stock outstanding   52,974 42,690 67,289 108,318
Shares granted   52,974 42,690 40,185  
Performance period   3 years      
Restricted Stock [Member] | 2013 Incentive Stock Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period   3 years      
Shares granted 37,550.54        
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 42,690 67,289  
Total Stockholder Return Based Awards [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total unrecognized compensation cost   $ 0.4      
Total unrecognized compensation cost, period of recognition   6 months