Quarterly report pursuant to Section 13 or 15(d)

Redeemable Noncontrolling Interests (Narrative) (Details)

v3.21.1
Redeemable Noncontrolling Interests (Narrative) (Details)
 3 Months Ended 12 Months Ended
Jun. 30, 2019
USD ($)
Jun. 28, 2019
USD ($)
Jun. 26, 2019
USD ($)
property
Mar. 10, 2017
USD ($)
Feb. 28, 2017
USD ($)
$ / shares
shares
Feb. 27, 2017
USD ($)
Feb. 03, 2017
USD ($)
$ / shares
shares
Mar. 31, 2021
USD ($)
$ / shares
Mar. 31, 2020
USD ($)
$ / shares
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Apr. 30, 2017
shares
Redeemable Noncontrolling Interest [Line Items]                        
General and administrative               $ 13,989,000 $ 15,818,000      
Expiration period               10 years        
Payment for borrowings               $ 33,000,000 121,000,000      
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%        
Mack-Cali Realty LP [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
General and administrative               $ 13,989,000 $ 15,818,000      
Common unit distribution per unit declared | $ / shares               $ 0 $ 0.20      
Payment for borrowings               $ 33,000,000 $ 121,000,000      
Series A Units [Member] | Mack-Cali Realty LP [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Preferred units shares issued | shares             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 | shares             28.15          
Expiration period             5 years          
Shares that may be converted to common units | shares             1,204,820          
Common unit distribution per unit declared | $ / shares             $ 35.52          
Series A-1 Units [Member] | Mack-Cali Realty LP [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Preferred units shares issued | shares         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 | shares         27.936              
Expiration period         5 years     5 years        
Shares that may be converted to common units | shares         257,375              
Common unit distribution per unit declared | $ / shares         $ 35.80              
Monaco (BLVD 495 N/S) [Member] | Series A-1 Units [Member] | Mack-Cali Realty LP [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Preferred units shares issued | shares         9,122              
Investment Agreement [Member] | Minimum [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Incremental closing payments, Limited Partnership interest                     $ 105,000,000  
RRLP [Member] | Cash Flow From Operations [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Annual return on the equity value               6.00%        
RRLP [Member] | Investment Agreement [Member] | Cash Flow From Capital Events, Distribution Four [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Capital base return               5.00%        
RRLP [Member] | Credit Enhancement Note [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Maximum borrowing capacity               $ 50,000,000        
Increased line of credit               $ 25,000,000        
Spread over LIBOR               50.00%        
Rockpoint [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Estimated redemption value               $ 476,000,000        
Rockpoint [Member] | Cash Flow From Operations [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Invested capital               400,000,000        
Rockpoint [Member] | Cash Flow From Capital Events, Distribution Five [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Invested capital               400,000,000        
Rockpoint [Member] | Cash Flow From Capital Events, Distribution Six [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Invested capital               $ 400,000,000        
Rockpoint [Member] | Distribution One [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Purchase price   $ 173,500,000                    
Purchase price, less distributions   198,500,000                    
Rockpoint [Member] | Distribution Two [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Purchase price, less distributions   $ 1,500,000                    
Rockpoint [Member] | Preferred Units [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Pro rata distribution               10.947%        
Rockpoint [Member] | Preferred Units [Member] | Cash Flow From Operations [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Pro rata distribution               21.89%        
Rockpoint [Member] | Preferred Units [Member] | Cash Flow From Capital Events, Distribution Five [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Pro rata distribution               21.89%        
Rockpoint [Member] | Investment Agreement [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Contributed equity value       $ 1,230,000,000                
Incremental closing payments, Limited Partnership interest     $ 46,000,000 $ 150,000,000         $ 45,000,000      
Rockpoint [Member] | Investment Agreement [Member] | Maximum [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Contributed amount to obtain equity units           $ 300,000,000            
Rockpoint [Member] | Add On Investment Agreement [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Contributed amount to obtain equity units     $ 100,000,000                  
Number of properties in which additional interest was acquired during period | property     2                  
Right of first refusal to invest               $ 100,000,000        
General and administrative                   $ 371,000    
Payment for borrowings $ 100,000,000                      
Rockpoint [Member] | Add On Investment Agreement [Member] | Maximum [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Contributed amount to obtain equity units               $ 154,000,000        
Rockpoint [Member] | RRLP [Member] | Cash Flow From Operations [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Annual return               6.00%        
Base return               4.64%        
Rockpoint [Member] | RRLP [Member] | Cash Flow From Capital Events, Distribution Three [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Base return               4.64%        
Rockpoint [Member] | RRLP [Member] | Cash Flow From Capital Events, Distribution Four [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Capital base return               4.64%        
Rockpoint [Member] | RRLP [Member] | Cash Flow From Capital Events, Distribution Five [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Internal rate of return               11.00%        
Rockpoint [Member] | RRLP [Member] | Cash Flow From Capital Events, Distribution Six [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Pro rata share               50.00%        
Rockpoint [Member] | RRLP [Member] | Investment Agreement [Member] | Cash Flow From Operations [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Base return               5.00%        
Rockpoint [Member] | RRLP [Member] | Investment Agreement [Member] | Cash Flow From Capital Events, Distribution Three [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Base return               95.00%        
RRT [Member] | Preferred Units [Member] | Cash Flow From Operations [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Pro rata distribution               2.65%        
RRT [Member] | Preferred Units [Member] | Cash Flow From Capital Events, Distribution Five [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Pro rata distribution               2.65%        
RRT [Member] | Preferred Units [Member] | Cash Flow From Capital Events, Distribution Six [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Pro rata distribution               1.325%        
RRT [Member] | Common Units [Member] | Cash Flow From Operations [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Pro rata distribution               75.46%        
RRT [Member] | Common Units [Member] | Cash Flow From Capital Events, Distribution Five [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Pro rata distribution               75.46%        
RRT [Member] | Common Units [Member] | Cash Flow From Capital Events, Distribution Six [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Pro rata distribution               87.728%        
RRT [Member] | RRLP [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Loan-to-value ratio     65.00%                  
Equity capitalization percent               10.00%        
RRT [Member] | RRLP [Member] | Cash Flow From Operations [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Base return               95.36%        
RRT [Member] | RRLP [Member] | Cash Flow From Capital Events, Distribution Three [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Base return               95.36%        
RRT [Member] | RRLP [Member] | Cash Flow From Capital Events, Distribution Four [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Capital base return               95.36%        
RRT [Member] | RRLP [Member] | Investment Agreement [Member] | Cash Flow From Operations [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Base return               95.00%        
RRT [Member] | RRLP [Member] | Investment Agreement [Member] | Cash Flow From Capital Events, Distribution Three [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Base return               5.00%        
RRT [Member] | RRLP [Member] | Investment Agreement [Member] | Cash Flow From Capital Events, Distribution Four [Member]                        
Redeemable Noncontrolling Interest [Line Items]                        
Capital base return               95.00%