Mack-Cali Realty Corporation Stockholders' Equity (Stock Options Plans) (Narrative) (Details) (USD $)
1 Months Ended3 Months Ended9 Months Ended9 Months Ended9 Months Ended
May 31, 2002
Sep. 30, 2011
years
Sep. 30, 2010
Sep. 30, 2011
sqft
years
Sep. 30, 2010
Feb. 18, 2011
Dec. 31, 2010
years
Sep. 30, 2011
2004 Incentive Stock Plan [Member]
May 31, 2004
2004 Incentive Stock Plan [Member]
Dec. 31, 1994
Employee And Director Plan [Member]
Sep. 30, 2011
Employee Plan [Member]
Dec. 31, 1994
Employee Plan [Member]
Dec. 31, 1994
Director Plan [Member]
Sep. 30, 2011
1994 And 1995 Employee Plans [Member]
Sep. 30, 2011
2000 Director And Employee Plan [Member]
Reserved stocks for issuance        2,500,0005,380,188 4,980,188400,000  
Description of amendments to both 2000 stock option plansshareholders of the Company approved amendments to both plans to increase the total shares reserved for issuance under both of the 2000 plans from 2,700,000 to 4,350,000 shares of the Company's common stock (from 2,500,000 to 4,000,000 shares under the 2000 Employee Plan and from 200,000 to 350,000 shares under the 2000 Director Plan).              
Shares issued     7,187,500 0       
Exercisable time period (years)          five  threeone
Stock option terms (years)   10           
Weighted average remaining contractual life (years) 1.2 1.2  1.7        
Proceeds from stock options exercised $ 1,585,000$ 960,000$ 3,048,000$ 1,473,000          
Total intrinsic value of options exercised $ 140,000$ 203,000$ 496,000$ 344,000