Consolidated Statements Of Operations - USD ($)
shares in Thousands, $ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
REVENUES                      
Base rents                 $ 501,334 $ 506,877 $ 487,041
Escalations and recoveries from tenants                 58,767 60,505 62,481
Real estate services                 23,129 26,589 29,620
Parking income                 20,270 13,630 11,124
Other income                 12,700 5,797 4,617
Total revenues $ 143,529 $ 160,018 $ 162,766 $ 149,887 $ 153,731 $ 157,517 $ 149,227 $ 152,923 616,200 613,398 594,883
EXPENSES                      
Real estate taxes                 81,364 87,379 82,688
Utilities                 42,598 49,624 55,965
Operating services                 107,379 103,954 107,951
Real estate services expenses                 23,394 26,260 25,583
General and administrative                 50,949 51,979 49,147
Acquisition-related costs                   2,880 1,560
Depreciation and amortization                 205,169 186,684 170,402
Impairments                     197,919
Total expenses                 510,853 508,760 691,215
Operating income (loss)                 105,347 104,638 (96,332)
OTHER (EXPENSE) INCOME                      
Interest expense                 (93,388) (94,889) (103,051)
Interest and other investment income (loss)                 2,766 1,614 794
Equity in earnings (loss) of unconsolidated joint ventures [1]                 (6,081) 18,788 (3,172)
Gain on change of control of interests                   15,347  
Realized gains (losses) and unrealized losses on disposition of rental property, net                 2,364 109,666 53,261
Gain on sale of investment in unconsolidated joint venture                 23,131 5,670 6,448
Loss from extinguishment of debt, net                 (421) (30,540)  
Total other income (expense)                 (71,629) 25,656 (45,720)
Net income (loss) 5,411 44,703 (39,125) 22,729 16,764 (9,605) 54,366 68,769 33,718 130,294 (142,052)
Noncontrolling interest in consolidated joint ventures                 1,018 651 1,044
Noncontrolling interest in Operating Partnership                 (2,711) (13,721) 15,256
Redeemable noncontrolling interest                 (8,840)    
Net income (loss) available to common shareholders $ 2,582 $ 38,054 $ (37,330) $ 19,879 $ 15,181 $ (8,541) $ 48,393 $ 62,191 $ 23,185 $ 117,224 $ (125,752)
Basic earnings per common share:                      
Net income (loss) available to common shareholders $ (0.01) $ 0.39 $ (0.44) $ 0.11 $ 0.17 $ (0.10) $ 0.54 $ 0.69 $ 0.06 $ 1.31 $ (1.41)
Diluted earnings per common share:                      
Net income (loss) available to common shareholders $ (0.01) $ 0.39 $ (0.44) $ 0.11 $ 0.17 $ (0.10) $ 0.54 $ 0.69 $ 0.06 $ 1.30 $ (1.41)
Basic weighted average shares outstanding                 90,005 89,746 89,291
Diluted weighted average shares outstanding                 100,703 100,498 100,222
Mack-Cali Realty LP [Member]                      
REVENUES                      
Base rents                 $ 501,334 $ 506,877 $ 487,041
Escalations and recoveries from tenants                 58,767 60,505 62,481
Real estate services                 23,129 26,589 29,620
Parking income                 20,270 13,630 11,124
Other income                 12,700 5,797 4,617
Total revenues $ 143,529 $ 160,018 $ 162,766 $ 149,887 $ 153,731 $ 157,517 $ 149,227 $ 152,923 616,200 613,398 594,883
EXPENSES                      
Real estate taxes                 81,364 87,379 82,688
Utilities                 42,598 49,624 55,965
Operating services                 107,379 103,954 107,951
Real estate services expenses                 23,394 26,260 25,583
General and administrative                 50,949 51,979 49,147
Acquisition-related costs                   2,880 1,560
Depreciation and amortization                 205,169 186,684 170,402
Impairments                     197,919
Total expenses                 510,853 508,760 691,215
Operating income (loss)                 105,347 104,638 (96,332)
OTHER (EXPENSE) INCOME                      
Interest expense                 (93,388) (94,889) (103,051)
Interest and other investment income (loss)                 2,766 1,614 794
Equity in earnings (loss) of unconsolidated joint ventures                 (6,081) 18,788 (3,172)
Gain on change of control of interests                   15,347  
Realized gains (losses) and unrealized losses on disposition of rental property, net                 2,364 109,666 53,261
Gain on sale of investment in unconsolidated joint venture                 23,131 5,670 6,448
Loss from extinguishment of debt, net                 (421) (30,540)  
Total other income (expense)                 (71,629) 25,656 (45,720)
Net income (loss) 5,411 44,703 (39,125) 22,729 16,764 (9,605) 54,366 68,769 33,718 130,294 (142,052)
Noncontrolling interest in consolidated joint ventures                 1,018 651 1,044
Redeemable noncontrolling interest                 (8,840)    
Net income (loss) available to common shareholders $ 2,881 $ 42,467 $ (41,626) $ 22,174 $ 16,955 $ (9,540) $ 54,055 $ 69,475 $ 25,896 $ 130,945 $ (141,008)
Basic earnings per common share:                      
Net income (loss) available to common shareholders $ (0.01) $ 0.39 $ (0.44) $ 0.11 $ 0.17 $ (0.10) $ 0.54 $ 0.69 $ 0.06 $ 1.31 $ (1.41)
Diluted earnings per common share:                      
Net income (loss) available to common shareholders $ (0.01) $ 0.39 $ (0.44) $ 0.11 $ 0.17 $ (0.10) $ 0.54 $ 0.69 $ 0.06 $ 1.30 $ (1.41)
Basic weighted average units outstanding                 100,410 100,245 100,222
Diluted weighted average units outstanding                 100,703 100,498 100,222
[1] Amounts are net of amortization of basis differences of $792, $436 and $336 for the years ended December 31, 2017, 2016 and 2015, respectively.