Quarterly report pursuant to Section 13 or 15(d)

Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Earnings Per Share/Unit) (Narrative) (Details)

v3.20.1
Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Earnings Per Share/Unit) (Narrative) (Details) - $ / shares
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unvested stock outstanding 42,690 66,321 42,690 67,289
Dividends declared per common share $ 0.20 $ 0.20    
Mack-Cali Realty LP [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Dividends declared per common share $ 0.20 $ 0.20    
Unvested Restricted Stock [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unvested stock outstanding 42,690 66,321    
Unvested Restricted Stock [Member] | Mack-Cali Realty LP [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unvested stock outstanding 42,690 66,321    
Unvested LTIP Units [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unvested stock outstanding 3,094,324 1,826,331    
Unvested LTIP Units [Member] | Mack-Cali Realty LP [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unvested performance shares 3,094,324 1,826,331    
Unvested AO LTIP Units [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unvested stock outstanding 625,000 625,000    
Unvested AO LTIP Units [Member] | Mack-Cali Realty LP [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unvested stock outstanding 625,000 625,000