Mack-Cali Realty Corporation Stockholders' Equity (Stock Options Plans) (Narrative) (Details) (USD $)
 3 Months Ended 12 Months Ended 3 Months Ended 3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Dec. 31, 2012
Mar. 31, 2013
2004 Incentive Stock Plan [Member]
May 31, 2004
2004 Incentive Stock Plan [Member]
Dec. 31, 1994
Employee And Director Plan [Member]
Mar. 31, 2013
Employee And Director Plan [Member]
Minimum [Member]
Mar. 31, 2013
Employee And Director Plan [Member]
Maximum [Member]
Mar. 31, 2013
2000 Employee Plan [Member]
Minimum [Member]
Mar. 31, 2013
2000 Employee Plan [Member]
Maximum [Member]
Mar. 31, 2013
2000 Director Plan [Member]
Minimum [Member]
Mar. 31, 2013
2000 Director Plan [Member]
Maximum [Member]
Mar. 31, 2013
Employee Plan [Member]
Dec. 31, 1994
Employee Plan [Member]
Dec. 31, 1994
Director Plan [Member]
Mar. 31, 2013
1994 And 1995 Employee Plans [Member]
Mar. 31, 2013
2000 Director Plan And Director Plan [Member]
Stock Option Activity [Line Items]                                  
Reserved stocks for issuance         2,500,000 5,380,188 2,700,000 4,350,000 2,500,000 4,000,000 200,000 350,000   4,980,188 400,000    
Shares issued       0                          
Exercisable time period                         5 years     3 years 1 year
Stock option terms 10 years                                
Weighted average remaining contractual life 1 year 6 months   1 month 6 days                            
Proceeds from stock options exercised $ 0 $ 0                              
Total intrinsic value of options exercised 0 0                              
Stock options expense $ 0 $ 0