Quarterly report pursuant to Section 13 or 15(d)

Redeemable Noncontrolling Interests (Narrative) (Details)

v3.8.0.1
Redeemable Noncontrolling Interests (Narrative) (Details) - USD ($)
 3 Months Ended
Jan. 24, 2018
Mar. 10, 2017
Feb. 28, 2017
Feb. 27, 2017
Feb. 03, 2017
Mar. 31, 2018
Apr. 30, 2017
Redeemable Noncontrolling Interest [Line Items]              
Expiration period           10 years  
Minimum [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Percentage of interest in venture           12.50%  
Maximum [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Percentage of interest in venture           85.00%  
Rockpoint [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Pro rata distribution           11.50%  
Estimated redemption value           $ 233,000,000  
Invested capital           $ 160,000,000  
RRT [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Pro rata distribution           88.50%  
Series A Units [Member] | Mack-Cali Realty LP [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Preferred units shares issued         42,800    
Preferred unit annual rate         3.50%    
Percentage of interest in venture         37.50%    
Preferred unit in operating partnership         $ 1,000    
Convertible preferred units         28.15    
Expiration period         5 years    
Shares converted to common units         1,204,820    
Common unit distribution per unit declared         $ 35.52    
Series A-1 Units [Member] | Mack-Cali Realty LP [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Preferred units shares issued     9,213       91
Preferred unit annual rate     3.50%        
Percentage of interest in venture     13.80%        
Preferred unit in operating partnership     $ 1,000        
Convertible preferred units     27.936        
Expiration period     5 years        
Shares converted to common units     257,375        
Common unit distribution per unit declared     $ 35.80        
Monaco [Member] | Series A-1 Units [Member] | Mack-Cali Realty LP [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Preferred units shares issued     9,122        
Investment Agreement [Member] | Rockpoint [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Contributed equity value   $ 1,230,000,000          
Incremental closing payments, Limited Partnership interest $ 10,000,000 $ 150,000,000          
Investment Agreement [Member] | Rockpoint [Member] | Minimum [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Incremental closing payments, Limited Partnership interest           $ 10,000,000  
Investment Agreement [Member] | Rockpoint [Member] | Maximum [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Contributed amount to obtain equity units       $ 300,000,000      
RRLP [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Annual return on the equity value           6.00%  
RRLP [Member] | Rockpoint [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Annual return           6.00%  
Base return           5.00%  
Internal rate of return           11.00%  
Pro rata share           50.00%  
RRLP [Member] | RRT [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Base return           95.00%  
Participation Rights [Member] | Maximum [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Contributed amount to obtain equity units           $ 200,000,000