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
|
|
|