Segment Reporting (Schedule Of Reconciliation Of Net Operating Income To Net Income Available To Common Shareholders) (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Segment Reporting Information [Line Items]        
Net operating income [1] $ 74,867 $ 47,416 $ 165,370 $ 125,656
Depreciation and amortization (48,117) (44,099) (134,639) (127,266)
Gain on change of control of interests     15,347  
Realized gains (losses) and unrealized losses on disposition of rental property, net (17,053) 18,718 68,664 53,261
Gain on sale of investment in unconsolidated joint venture     5,670 6,448
Loss from extinguishment of debt, net (19,302)   (6,882)  
Impairments   (164,176)   (164,176)
Net income (loss) (9,605) (142,141) 113,530 (106,077)
Noncontrolling interest in consolidated joint ventures 65 (281) 460 582
Noncontrolling interest in Operating Partnership 999 15,530 (11,947) 11,461
Net income (loss) available to common shareholders (8,541) (126,892) 102,043 (94,034)
Mack Cali Realty LP [Member]        
Segment Reporting Information [Line Items]        
Net operating income 74,867 47,416 165,370 125,656
Depreciation and amortization (48,117) (44,099) (134,639) (127,266)
Gain on change of control of interests     15,347  
Realized gains (losses) and unrealized losses on disposition of rental property, net (17,053) 18,718 68,664 53,261
Gain on sale of investment in unconsolidated joint venture     5,670 6,448
Loss from extinguishment of debt, net (19,302)   (6,882)  
Impairments   (164,176)   (164,176)
Net income (loss) (9,605) (142,141) 113,530 (106,077)
Noncontrolling interest in consolidated joint ventures 65 (281) 460 582
Net income (loss) available to common shareholders $ (9,540) $ (142,422) $ 113,990 $ (105,495)
[1] Net operating income represents total revenues less total operating and interest expenses (as defined in Note "a"), plus equity in earnings (loss) of unconsolidated joint ventures, for the period.