Mack-Cali Realty Corporation Stockholders' Equity (Share Repurchase Program And Dividend Reinvestment And Stock Purchase Plan) (Narrative) (Details) (USD $)
3 Months Ended 31 Months Ended
Mar. 31, 2015
Mar. 31, 2015
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
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