Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Earnings Per Share/Unit) (Narrative) (Details) - $ / shares |
12 Months Ended | |||
|---|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Unvested stock outstanding | 67,289 | 108,318 | 145,278 | 136,220 |
| Dividends declared per common share | $ 0.80 | $ 0.75 | $ 0.60 | |
| Mack-Cali Realty LP [Member] | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Distribution declared per common unit | $ 0.80 | $ 0.75 | $ 0.60 | |
| Unvested Restricted Stock [Member] | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Unvested stock outstanding | 67,289 | 95,801 | 120,245 | |
| Unvested Restricted Stock [Member] | Mack-Cali Realty LP [Member] | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Unvested stock outstanding | 67,289 | 95,801 | 120,245 | |