Consolidated Statements Of Operations - USD ($)
shares in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
REVENUES        
Revenue from leases $ 116,784,000 $ 113,885,000 $ 239,799,000 $ 239,578,000
Total revenues 130,461,000 126,589,000 264,710,000 265,556,000
EXPENSES        
Real estate taxes 16,597,000 17,966,000 33,674,000 36,327,000
Operating services 26,161,000 22,939,000 51,123,000 48,557,000
Real estate services expenses 3,979,000 4,360,000 8,245,000 9,296,000
Leasing personnel costs 542,000   1,284,000  
General and administrative 16,427,000 13,455,000 29,020,000 29,540,000
Depreciation and amortization 49,352,000 41,413,000 97,398,000 82,710,000
Property impairments 5,802,000   5,802,000  
Land impairments 2,499,000   2,499,000  
Total expenses 128,815,000 107,688,000 246,952,000 226,489,000
OTHER (EXPENSE) INCOME        
Interest expense (23,515,000) (18,999,000) (48,289,000) (39,074,000)
Interest and other investment income (loss) 515,000 641,000 1,339,000 1,769,000
Equity in earnings (loss) of unconsolidated joint ventures (88,000) (52,000) (769,000) 1,520,000
Gain on change of control of interests     13,790,000  
Realized gains (losses) and unrealized losses on disposition of rental property, net 255,000 1,010,000 268,364,000 59,196,000
Gain on disposition of developable land 270,000   270,000  
Gain on sale of investment in unconsolidated joint venture     903,000  
Gain (loss) from extinguishment of debt, net 588,000 0 1,899,000 (10,289,000)
Total other income (expense) (21,975,000) (17,400,000) 237,507,000 13,122,000
Net income (loss) (20,329,000) 1,501,000 255,265,000 52,189,000
Noncontrolling interests in consolidated joint ventures 847,000 95,000 2,095,000 125,000
Noncontrolling interests in Operating Partnership 2,434,000 142,000 (25,246,000) (4,741,000)
Redeemable noncontrolling interests (5,006,000) (2,989,000) (9,673,000) (5,788,000)
Net income (loss) available to common shareholders $ (22,054,000) $ (1,251,000) $ 222,441,000 $ 41,785,000
Basic earnings per common share:        
Net income (loss) available to common shareholders $ (0.43) $ (0.05) $ 2.24 $ 0.39
Diluted earnings per common share:        
Net income (loss) available to common shareholders $ (0.43) $ (0.05) $ 2.24 $ 0.39
Basic weighted average shares outstanding 90,533 90,330 90,516 90,297
Diluted weighted average shares outstanding 100,523 100,598 100,825 100,607
Real Estate Services [Member]        
REVENUES        
Total revenues $ 3,530,000 $ 4,074,000 $ 7,372,000 $ 8,735,000
Parking Income [Member]        
REVENUES        
Total revenues 5,563,000 5,757,000 10,504,000 11,084,000
Hotel Income [Member]        
REVENUES        
Total revenues 2,094,000   2,377,000  
Other Income [Member]        
REVENUES        
Total revenues 2,490,000 2,873,000 4,658,000 6,159,000
Utilities [Member]        
EXPENSES        
Utilities 7,456,000 7,555,000 17,907,000 20,059,000
Mack-Cali Realty LP [Member]        
REVENUES        
Revenue from leases 116,784,000 113,885,000 239,799,000 239,578,000
Total revenues 130,461,000 126,589,000 264,710,000 265,556,000
EXPENSES        
Real estate taxes 16,597,000 17,966,000 33,674,000 36,327,000
Utilities 7,456,000 7,555,000 17,907,000 20,059,000
Operating services 26,161,000 22,939,000 51,123,000 48,557,000
Real estate services expenses 3,979,000 4,360,000 8,245,000 9,296,000
Leasing personnel costs 542,000   1,284,000  
General and administrative 16,427,000 13,455,000 29,020,000 29,540,000
Depreciation and amortization 49,352,000 41,413,000 97,398,000 82,710,000
Property impairments 5,802,000   5,802,000  
Land impairments 2,499,000   2,499,000  
Total expenses 128,815,000 107,688,000 246,952,000 226,489,000
OTHER (EXPENSE) INCOME        
Interest expense (23,515,000) (18,999,000) (48,289,000) (39,074,000)
Interest and other investment income (loss) 515,000 641,000 1,339,000 1,769,000
Equity in earnings (loss) of unconsolidated joint ventures (88,000) (52,000) (769,000) 1,520,000
Gain on change of control of interests     13,790,000  
Realized gains (losses) and unrealized losses on disposition of rental property, net 255,000 1,010,000 268,364,000 59,196,000
Gain on disposition of developable land 270,000   270,000  
Gain on sale of investment in unconsolidated joint venture     903,000  
Gain (loss) from extinguishment of debt, net 588,000   1,899,000 (10,289,000)
Total other income (expense) (21,975,000) (17,400,000) 237,507,000 13,122,000
Net income (loss) (20,329,000) 1,501,000 255,265,000 52,189,000
Noncontrolling interests in consolidated joint ventures 847,000 95,000 2,095,000 125,000
Redeemable noncontrolling interests (5,006,000) (2,989,000) (9,673,000) (5,788,000)
Net income (loss) available to common shareholders $ (24,488,000) $ (1,393,000) $ 247,687,000 $ 46,526,000
Basic earnings per common share:        
Net income (loss) available to common shareholders $ (0.43) $ (0.05) $ 2.24 $ 0.39
Diluted earnings per common share:        
Net income (loss) available to common shareholders $ (0.43) $ (0.05) $ 2.24 $ 0.39
Basic weighted average units outstanding 100,523 100,598 100,631 100,552
Diluted weighted average units outstanding 100,523 100,598 100,825 100,607
Mack-Cali Realty LP [Member] | Real Estate Services [Member]        
REVENUES        
Total revenues $ 3,530,000 $ 4,074,000 $ 7,372,000 $ 8,735,000
Mack-Cali Realty LP [Member] | Parking Income [Member]        
REVENUES        
Total revenues 5,563,000 5,757,000 10,504,000 11,084,000
Mack-Cali Realty LP [Member] | Hotel Income [Member]        
REVENUES        
Total revenues 2,094,000   2,377,000  
Mack-Cali Realty LP [Member] | Other Income [Member]        
REVENUES        
Total revenues $ 2,490,000 $ 2,873,000 $ 4,658,000 $ 6,159,000