Consolidated Statements Of Cash Flows - USD ($)
 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES    
Net income (loss) $ 52,189,000 $ (16,396,000)
Adjustments to reconcile net income (loss) to net cash provided by Operating activities:    
Depreciation and amortization, including related intangible assets 79,827,000 102,389,000
Amortization of directors deferred compensation stock units 251,000 236,000
Amortization of stock compensation 3,189,000 3,099,000
Amortization of deferred financing costs 2,241,000 2,278,000
Amortization of debt discount and mark-to-market (474,000) 78,000
Write off of unamortized deferred financing costs related to early extinguishment 105,000 0
Equity in (earnings) loss of unconsolidated joint ventures (1,520,000) 3,349,000
Distributions of cumulative earnings from unconsolidated joint ventures 3,469,000 3,822,000
Realized (gains) losses and unrealized losses on disposition of rental property, net (59,196,000) 33,448,000
Gain on sale of investments in unconsolidated joint ventures   (12,563,000)
Loss from extinguishment of debt 10,289,000 239,000
Changes in operating assets and liabilities:    
Increase in unbilled rents receivable, net (3,497,000) (5,927,000)
Increase in deferred charges, goodwill and other assets (8,510,000) (9,028,000)
Decrease in accounts receivable, net 396,000 1,911,000
Increase (decrease) in accounts payable, accrued expenses and other liabilities 7,033,000 (9,544,000)
(Decrease) Increase in rents received in advance and security deposits (2,855,000) 5,599,000
(Decrease) Increase in accrued interest payable (1,001,000) 772,000
Net cash provided by operating activities 81,936,000 103,762,000
CASH FLOWS FROM INVESTING ACTIVITIES    
Rental property acquisitions and related intangibles (4,854,000) (536,224,000)
Rental property additions and improvements (97,085,000) (46,103,000)
Development of rental property and other related costs (105,749,000) (133,685,000)
Proceeds from the sales of rental property 244,754,000 48,221,000
Proceeds from the sale of investments in unconsolidated joint ventures   14,849,000
Investments in notes receivable   (2,254,000)
Repayment of notes receivable 6,366,000 9,341,000
Investment in unconsolidated joint ventures (3,352,000) (11,422,000)
Distributions in excess of cumulative earnings from unconsolidated joint ventures 7,806,000 3,169,000
Proceeds from investment receivable   3,625,000
Net cash provided by (used in) investing activities 47,886,000 (650,483,000)
CASH FLOW FROM FINANCING ACTIVITIES    
Borrowings from revolving credit facility 371,000,000 334,000,000
Repayment of revolving credit facility (338,000,000) (521,000,000)
Borrowings from unsecured term loan   325,000,000
Proceeds from mortgages and loans payable 79,748,000 307,980,000
Repayment of mortgages, loans payable and other obligations (277,637,000) (3,109,000)
Acquisition of noncontrolling interests   (2,011,000)
Issuance of redeemable noncontrolling interests, net 65,000,000 139,002,000
Payment of financing costs (255,000) (8,485,000)
(Distribution to) contributions from noncontrolling interests 51,000 (18,000)
Payments of dividends and distributions (45,916,000) (32,315,000)
Net cash (used in) provided by financing activities (146,009,000) 539,044,000
Net decrease in cash and cash equivalents (16,187,000) (7,677,000)
Cash, cash equivalents and restricted cash, beginning of period [1] 67,972,000 85,563,000
Cash, cash equivalents and restricted cash, end of period [2] 51,785,000 77,886,000
Mack-Cali Realty LP [Member]    
CASH FLOWS FROM OPERATING ACTIVITIES    
Net income (loss) 52,189,000 (16,396,000)
Adjustments to reconcile net income (loss) to net cash provided by Operating activities:    
Depreciation and amortization, including related intangible assets 79,827,000 102,389,000
Amortization of directors deferred compensation stock units 251,000 236,000
Amortization of stock compensation 3,189,000 3,099,000
Amortization of deferred financing costs 2,241,000 2,278,000
Amortization of debt discount and mark-to-market (474,000) 78,000
Write off of unamortized deferred financing costs related to early extinguishment 105,000  
Equity in (earnings) loss of unconsolidated joint ventures (1,520,000) 3,349,000
Distributions of cumulative earnings from unconsolidated joint ventures 3,469,000 3,822,000
Realized (gains) losses and unrealized losses on disposition of rental property, net (59,196,000) 33,448,000
Gain on sale of investments in unconsolidated joint ventures   (12,563,000)
Loss from extinguishment of debt 10,289,000 239,000
Changes in operating assets and liabilities:    
Increase in unbilled rents receivable, net (3,497,000) (5,927,000)
Increase in deferred charges, goodwill and other assets (8,510,000) (9,028,000)
Decrease in accounts receivable, net 396,000 1,911,000
Increase (decrease) in accounts payable, accrued expenses and other liabilities 7,033,000 (9,544,000)
(Decrease) Increase in rents received in advance and security deposits (2,855,000) 5,599,000
(Decrease) Increase in accrued interest payable (1,001,000) 772,000
Net cash provided by operating activities 81,936,000 103,762,000
CASH FLOWS FROM INVESTING ACTIVITIES    
Rental property acquisitions and related intangibles (4,854,000) (536,224,000)
Rental property additions and improvements (97,085,000) (46,103,000)
Development of rental property and other related costs (105,749,000) (133,685,000)
Proceeds from the sales of rental property 244,754,000 48,221,000
Proceeds from the sale of investments in unconsolidated joint ventures   14,849,000
Investments in notes receivable   (2,254,000)
Repayment of notes receivable 6,366,000 9,341,000
Investment in unconsolidated joint ventures (3,352,000) (11,422,000)
Distributions in excess of cumulative earnings from unconsolidated joint ventures 7,806,000 3,169,000
Proceeds from investment receivable   3,625,000
Net cash provided by (used in) investing activities 47,886,000 (650,483,000)
CASH FLOW FROM FINANCING ACTIVITIES    
Borrowings from revolving credit facility 371,000,000 334,000,000
Repayment of revolving credit facility (338,000,000) (521,000,000)
Borrowings from unsecured term loan   325,000,000
Proceeds from mortgages and loans payable 79,748,000 307,980,000
Repayment of mortgages, loans payable and other obligations (277,637,000) (3,109,000)
Acquisition of noncontrolling interests   (2,011,000)
Issuance of redeemable noncontrolling interests, net 65,000,000 139,002,000
Payment of financing costs (255,000) (8,485,000)
(Distribution to) contributions from noncontrolling interests 51,000 (18,000)
Payments of dividends and distributions (45,916,000) (32,315,000)
Net cash (used in) provided by financing activities (146,009,000) 539,044,000
Net decrease in cash and cash equivalents (16,187,000) (7,677,000)
Cash, cash equivalents and restricted cash, beginning of period [1] 67,972,000 85,563,000
Cash, cash equivalents and restricted cash, end of period [2] $ 51,785,000 $ 77,886,000
[1] Includes Restricted Cash of $39,792 and $53,952 as of December 31, 2017 and 2016, respectively, pursuant to the adoption of ASU 2016-15.
[2] Includes Restricted Cash of $22,121 and $56,167 as of June 30, 2018 and 2017, respectively, pursuant to the adoption of ASU 2016-15.