Quarterly report pursuant to Section 13 or 15(d)

Redeemable Noncontrolling Interests (Narrative) (Details)

v3.19.1
Redeemable Noncontrolling Interests (Narrative) (Details) - USD ($)
 3 Months Ended 12 Months Ended
Mar. 10, 2017
Feb. 28, 2017
Feb. 27, 2017
Feb. 03, 2017
Mar. 31, 2019
Dec. 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         20.00%    
Maximum [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Percentage of interest in venture         85.00%    
Rockpoint [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Pro rata distribution         19.60%    
Estimated redemption value         $ 376,000,000    
Invested capital         $ 300,000,000    
RRT [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Pro rata distribution         80.40%    
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 that may be 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 that may be 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 $ 150,000,000       $ 45,000,000    
Investment Agreement [Member] | Rockpoint [Member] | Minimum [Member]              
Redeemable Noncontrolling Interest [Line Items]              
Incremental closing payments, Limited Partnership interest           $ 105,000,000  
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