Consolidated Statements Of Operations - USD ($)
shares in Thousands, $ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
REVENUES        
Revenue from leases $ 72,243 $ 67,396 $ 206,950 $ 205,732
Total revenues 83,744 79,197 241,084 236,999
EXPENSES        
Real estate taxes 11,905 11,004 35,958 32,920
Utilities 3,573 3,598 10,816 10,564
Operating services 17,291 19,116 51,831 51,179
Real estate services expenses 3,307 3,299 9,838 10,107
General and administrative 11,292 26,361 43,347 59,423
Dead deal and transaction-related costs 3,671 2,583 6,416 2,583
Depreciation and amortization 29,344 31,769 86,410 93,104
Property impairments   36,582 6,041 36,582
Land and other impairments, net 3,401 1,292 11,333 23,401
Total expenses 83,784 135,604 261,990 319,863
OTHER (EXPENSE) INCOME        
Interest expense (15,200) (20,265) (49,364) (61,794)
Interest and other investment income (loss) (4,731) 3 (4,620) 42
Equity in earnings (loss) of unconsolidated joint ventures (1,724) 1,373 (2,831) (281)
Realized gains (losses) and unrealized gains (losses) on disposition of rental property, net (3,000)   521 (7,915)
Gain on disposition of developable land     111 4,813
Gain (loss) on sale of unconsolidated joint venture interests (1,886)   (1,886)  
Loss from extinguishment of debt, net     (46,735)  
Total other income (expense) (26,541) (18,889) (104,804) (65,135)
Loss from continuing operations (26,581) (75,296) (125,710) (147,999)
Discontinued operations:        
Income from discontinued operations 180 18,403 13,939 60,004
Realized gains (losses) and unrealized gains (losses) on disposition of rental property and impairments, net 609 15,775 25,469 (23,901)
Total discontinued operations, net 789 34,178 39,408 36,103
Net loss (25,792) (41,118) (86,302) (111,896)
Noncontrolling interests in consolidated joint ventures 1,137 895 3,670 1,900
Noncontrolling interests in Operating Partnership of income from continuing operations 2,884 7,769 12,858 15,859
Noncontrolling interests in Operating Partnership in discontinued operations (72) (3,283) (3,583) (3,469)
Redeemable noncontrolling interests (6,471) (6,471) (19,413) (19,413)
Net loss available to common shareholders $ (28,314) $ (42,208) $ (92,770) $ (117,019)
Basic earnings per common share:        
Loss from continuing operations $ (0.34) $ (0.83) $ (1.47) $ (1.73)
Discontinued operations 0.01 0.34 0.39 0.36
Net loss available to common shareholders (0.33) (0.49) (1.08) (1.37)
Diluted earnings per common share:        
Loss from continuing operations (0.34) (0.83) (1.47) (1.73)
Discontinued operations 0.01 0.34 0.39 0.36
Net loss available to common shareholders $ (0.33) $ (0.49) $ (1.08) $ (1.37)
Basic weighted average shares outstanding 90,941 90,671 90,803 90,639
Diluted weighted average shares outstanding 99,975 100,307 99,870 100,235
Real Estate Services [Member]        
REVENUES        
Total revenues $ 2,628 $ 2,876 $ 7,748 $ 8,624
Parking Income [Member]        
REVENUES        
Total revenues 3,950 4,033 10,520 12,332
Hotel Income [Member]        
REVENUES        
Total revenues 3,018 893 6,785 3,290
Other Income [Member]        
REVENUES        
Total revenues 1,905 3,999 9,081 7,021
Mack-Cali Realty LP [Member]        
REVENUES        
Revenue from leases 72,243 67,396 206,950 205,732
Total revenues 83,744 79,197 241,084 236,999
EXPENSES        
Real estate taxes 11,905 11,004 35,958 32,920
Utilities 3,573 3,598 10,816 10,564
Operating services 17,291 19,116 51,831 51,179
Real estate services expenses 3,307 3,299 9,838 10,107
General and administrative 11,292 26,361 43,347 59,423
Dead deal and transaction-related costs 3,671 2,583 6,416 2,583
Depreciation and amortization 29,344 31,769 86,410 93,104
Property impairments   36,582 6,041 36,582
Land and other impairments, net 3,401 1,292 11,333 23,401
Total expenses 83,784 135,604 261,990 319,863
OTHER (EXPENSE) INCOME        
Interest expense (15,200) (20,265) (49,364) (61,794)
Interest and other investment income (loss) (4,731) 3 (4,620) 42
Equity in earnings (loss) of unconsolidated joint ventures (1,724) 1,373 (2,831) (281)
Realized gains (losses) and unrealized gains (losses) on disposition of rental property, net (3,000)   521 (7,915)
Gain on disposition of developable land     111 4,813
Gain (loss) on sale of unconsolidated joint venture interests (1,886)   (1,886)  
Loss from extinguishment of debt, net     (46,735)  
Total other income (expense) (26,541) (18,889) (104,804) (65,135)
Loss from continuing operations (26,581) (75,296) (125,710) (147,999)
Discontinued operations:        
Income from discontinued operations 180 18,403 13,939 60,004
Realized gains (losses) and unrealized gains (losses) on disposition of rental property and impairments, net 609 15,775 25,469 (23,901)
Total discontinued operations, net 789 34,178 39,408 36,103
Net loss (25,792) (41,118) (86,302) (111,896)
Noncontrolling interests in consolidated joint ventures 1,137 895 3,670 1,900
Redeemable noncontrolling interests (6,471) (6,471) (19,413) (19,413)
Net loss available to common shareholders $ (31,126) $ (46,694) $ (102,045) $ (129,409)
Basic earnings per common share:        
Loss from continuing operations $ (0.34) $ (0.83) $ (1.47) $ (1.73)
Discontinued operations 0.01 0.34 0.39 0.36
Net loss available to common shareholders (0.33) (0.49) (1.08) (1.37)
Diluted earnings per common share:        
Loss from continuing operations (0.34) (0.83) (1.47) (1.73)
Discontinued operations 0.01 0.34 0.39 0.36
Net loss available to common shareholders $ (0.33) $ (0.49) $ (1.08) $ (1.37)
Basic weighted average units outstanding 99,975 100,307 99,870 100,235
Diluted weighted average units outstanding 99,975 100,307 99,870 100,235
Mack-Cali Realty LP [Member] | Real Estate Services [Member]        
REVENUES        
Total revenues $ 2,628 $ 2,876 $ 7,748 $ 8,624
Mack-Cali Realty LP [Member] | Parking Income [Member]        
REVENUES        
Total revenues 3,950 4,033 10,520 12,332
Mack-Cali Realty LP [Member] | Hotel Income [Member]        
REVENUES        
Total revenues 3,018 893 6,785 3,290
Mack-Cali Realty LP [Member] | Other Income [Member]        
REVENUES        
Total revenues $ 1,905 $ 3,999 $ 9,081 $ 7,021