Consolidated Statements Of Operations - USD ($)
shares in Thousands, $ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
REVENUES                      
Total revenues $ 132,936 $ 132,114 $ 126,589 $ 138,967 $ 143,529 $ 160,018 $ 162,766 $ 149,887 $ 530,606 $ 616,200 $ 613,398
EXPENSES                      
Real estate taxes                 64,555 81,364 87,379
Utilities                 39,054 42,598 49,624
Operating services                 102,626 107,379 103,954
Real estate services expenses                 17,919 23,394 26,260
General and administrative                 53,988 50,949 51,979
Acquisition-related costs                     2,880
Depreciation and amortization                 174,847 205,169 186,684
Land impairments                 24,566    
Total expenses                 477,555 510,853 508,760
OTHER (EXPENSE) INCOME                      
Interest expense                 (83,754) (93,388) (94,889)
Interest and other investment income (loss)                 3,389 2,766 1,614
Equity in earnings (loss) of unconsolidated joint ventures                 (127) (6,081) 18,788
Gain on change of control of interests                 14,217   15,347
Realized gains (losses) and unrealized losses on disposition of rental property, net                 99,436 2,364 109,666
Gain on disposition of developable land                 30,939    
Gain on sale of investment in unconsolidated joint venture                   23,131 5,670
Loss from extinguishment of debt, net                 (10,750) (421) (30,540)
Total other income (expense)                 53,350 (71,629) 25,656
Net income 52,523 1,689 1,501 50,688 5,411 44,703 (39,125) 22,729 106,401 33,718 130,294
Noncontrolling interest in consolidated joint ventures                 1,216 1,018 651
Noncontrolling interest in Operating Partnership                 (9,527) (2,711) (13,721)
Redeemable noncontrolling interest                 (13,979) (8,840)  
Net income available to common shareholders $ 43,804 $ (1,478) $ (1,251) $ 43,036 $ 2,582 $ 38,054 $ (37,330) $ 19,879 $ 84,111 $ 23,185 $ 117,224
Basic earnings per common share:                      
Net income available to common shareholders $ 0.45 $ (0.05) $ (0.05) $ 0.45 $ (0.01) $ 0.39 $ (0.44) $ 0.11 $ 0.80 $ 0.06 $ 1.31
Diluted earnings per common share:                      
Net income available to common shareholders $ 0.45 $ (0.05) $ (0.05) $ 0.45 $ (0.01) $ 0.39 $ (0.44) $ 0.11 $ 0.80 $ 0.06 $ 1.30
Basic weighted average shares outstanding                 90,388 90,005 89,746
Diluted weighted average shares outstanding                 100,724 100,703 100,498
Base Rents [Member]                      
REVENUES                      
Total revenues                 $ 436,222 $ 501,334 $ 506,877
Escalations And Recoveries From Tenants [Member]                      
REVENUES                      
Total revenues                 44,121 58,767 60,505
Real Estate Services [Member]                      
REVENUES                      
Total revenues                 17,094 23,129 26,589
Parking Income [Member]                      
REVENUES                      
Total revenues                 22,117 20,270 13,630
Other Income [Member]                      
REVENUES                      
Total revenues                 11,052 12,700 5,797
Mack-Cali Realty LP [Member]                      
REVENUES                      
Total revenues $ 132,936 $ 132,114 $ 126,589 $ 138,967 $ 143,529 $ 160,018 $ 162,766 $ 149,887 530,606 616,200 613,398
EXPENSES                      
Real estate taxes                 64,555 81,364 87,379
Utilities                 39,054 42,598 49,624
Operating services                 102,626 107,379 103,954
Real estate services expenses                 17,919 23,394 26,260
General and administrative                 53,988 50,949 51,979
Acquisition-related costs                     2,880
Depreciation and amortization                 174,847 205,169 186,684
Land impairments                 24,566    
Total expenses                 477,555 510,853 508,760
OTHER (EXPENSE) INCOME                      
Interest expense                 (83,754) (93,388) (94,889)
Interest and other investment income (loss)                 3,389 2,766 1,614
Equity in earnings (loss) of unconsolidated joint ventures                 (127) (6,081) 18,788
Gain on change of control of interests                 14,217   15,347
Realized gains (losses) and unrealized losses on disposition of rental property, net                 99,436 2,364 109,666
Gain on disposition of developable land                 30,939    
Gain on sale of investment in unconsolidated joint venture                   23,131 5,670
Loss from extinguishment of debt, net                 (10,750) (421) (30,540)
Total other income (expense)                 53,350 (71,629) 25,656
Net income 52,523 1,689 1,501 50,688 5,411 44,703 (39,125) 22,729 106,401 33,718 130,294
Noncontrolling interest in consolidated joint ventures                 1,216 1,018 651
Redeemable noncontrolling interest                 (13,979) (8,840)  
Net income available to common shareholders $ 48,757 $ (1,645) $ (1,393) $ 47,919 $ 2,881 $ 42,467 $ (41,626) $ 22,174 $ 93,638 $ 25,896 $ 130,945
Basic earnings per common share:                      
Net income available to common shareholders $ 0.45 $ (0.05) $ (0.05) $ 0.45 $ (0.01) $ 0.39 $ (0.44) $ 0.11 $ 0.80 $ 0.06 $ 1.31
Diluted earnings per common share:                      
Net income available to common shareholders $ 0.45 $ (0.05) $ (0.05) $ 0.45 $ (0.01) $ 0.39 $ (0.44) $ 0.11 $ 0.80 $ 0.06 $ 1.30
Basic weighted average units outstanding                 100,634 100,410 100,245
Diluted weighted average units outstanding                 100,724 100,703 100,498
Mack-Cali Realty LP [Member] | Base Rents [Member]                      
REVENUES                      
Total revenues                 $ 436,222 $ 501,334 $ 506,877
Mack-Cali Realty LP [Member] | Escalations And Recoveries From Tenants [Member]                      
REVENUES                      
Total revenues                 44,121 58,767 60,505
Mack-Cali Realty LP [Member] | Real Estate Services [Member]                      
REVENUES                      
Total revenues                 17,094 23,129 26,589
Mack-Cali Realty LP [Member] | Parking Income [Member]                      
REVENUES                      
Total revenues                 22,117 20,270 13,630
Mack-Cali Realty LP [Member] | Other Income [Member]                      
REVENUES                      
Total revenues                 $ 11,052 $ 12,700 $ 5,797