Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital (Share/Unit Repurchase Program And Dividend Reinvestment And Stock Purchase Plan) (Narrative) (Details) - USD ($) |
12 Months Ended | 64 Months Ended | |
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2012 |
Dec. 31, 2017 |
|
| Stockolders Equity [Line Items] | |||
| Date share repurchase program was initiated | September 2012 | ||
| Capacity of share repurchase program | $ 150,000,000 | $ 150,000,000 | |
| Shares purchased and retired | 394,625 | ||
| Aggregate cost of stock repurchased | $ 11,000,000 | ||
| Capacity available for additional repurchase of outstanding common stock | $ 139,000,000 | $ 139,000,000 | |
| Proceeds from sale of common units | $ 11,000,000 | ||
| Dividend Reinvestment And Stock Purchase Plan [Member] | |||
| Stockolders Equity [Line Items] | |||
| Common stock reserved for future issuance | 5,500,000 | 5,500,000 | |
| Monthly cash investment without restriction, maximum | $ 5,000 | ||