Quarterly report pursuant to Section 13 or 15(d)

Noncontrolling Interests In Subsidiaries (Narrative) (Details)

v3.21.2
Noncontrolling Interests In Subsidiaries (Narrative) (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Mar. 31, 2019
Sep. 30, 2021
Dec. 31, 2020
Noncontrolling Interest [Line Items]      
Number of common shares received upon redemption of common units   1  
Rebalance of ownership percentage   $ 0.5  
Participation Rights [Member]      
Noncontrolling Interest [Line Items]      
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%
Flex Portfolio [Member]      
Noncontrolling Interest [Line Items]      
Redemption of common units, shares   41,750  
Proceeds from sale of properties   $ 0.7  
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