Quarterly report pursuant to Section 13 or 15(d)

Noncontrolling Interests In Subsidiaries (Narrative) (Details)

v3.21.1
Noncontrolling Interests In Subsidiaries (Narrative) (Details)
$ in Millions
 3 Months Ended
Jun. 05, 2015
shares
Mar. 31, 2021
USD ($)
property
shares
Mar. 31, 2019
shares
Dec. 31, 2020
Noncontrolling Interest [Line Items]        
Number of common shares received upon redemption of common units   1    
Rebalance of ownership percentage | $   $ 1.6    
Shares granted 800,000      
Exercisable period   10 years    
Participation Rights [Member]        
Noncontrolling Interest [Line Items]        
Number of properties | property   1    
Excess net cash flow remaining after the distribution to the Company   50.00%    
Internal rate of return   10.00%    
Mack-Cali Realty LP [Member]        
Noncontrolling Interest [Line Items]        
Percentage of noncontrolling interest   9.00%   9.60%
Future Developments [Member] | Participation Rights [Member]        
Noncontrolling Interest [Line Items]        
Number of properties | property   1    
Disposal Group, Not Discontinued Operations [Member] | Flex Portfolio [Member]        
Noncontrolling Interest [Line Items]        
Redemption of common units, shares   678,302    
Proceeds from sale of properties | $   $ 10.5    
AO LTIP Units Award [Member]        
Noncontrolling Interest [Line Items]        
Exercisable period   10 years    
AO LTIP Units Award [Member] | Messr DeMarco, CEO [Member]        
Noncontrolling Interest [Line Items]        
Shares granted     625,000