Consolidated Statements Of Cash Flows - USD ($)
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES    
Net income $ 50,688,000 $ 22,729,000
Adjustments to reconcile net income to net cash provided by Operating activities:    
Depreciation and amortization, including related intangible assets 39,489,000 46,338,000
Amortization of directors deferred compensation stock units 125,000 115,000
Amortization of stock compensation 2,532,000 1,053,000
Amortization of deferred financing costs 1,096,000 1,103,000
Amortization of debt discount and mark-to-market (237,000) 241,000
Write-off of unamortized deferred finance costs related to early extinguishment 105,000 0
Equity in (earnings) loss of unconsolidated joint ventures (1,572,000) 51,000
Distributions of cumulative earnings from unconsolidated joint ventures 2,119,000 2,684,000
Realized (gains) losses and unrealized losses on disposition of rental property, net (58,186,000) (5,506,000)
Gain on sale of investments in unconsolidated joint ventures   (12,563,000)
Loss (gain) from extinguishment of debt 10,289,000 239,000
Changes in operating assets and liabilities:    
Increase in unbilled rents receivable, net (3,788,000) (2,950,000)
Increase in deferred charges, goodwill and other assets (1,899,000) (2,842,000)
(Increase) decrease in accounts receivable, net (545,000) 13,000
Increase (decrease) in accounts payable, accrued expenses and other liabilities 14,134,000 (11,396,000)
(Decrease) Increase in rents received in advance and security deposits (2,118,000) 3,891,000
Increase in accrued interest payable 4,667,000 8,113,000
Net cash provided by operating activities 56,899,000 51,313,000
CASH FLOWS FROM INVESTING ACTIVITIES    
Rental property acquisitions and related intangibles (365,000) (413,115,000)
Rental property additions and improvements (55,935,000) (22,471,000)
Development of rental property and other related costs (50,038,000) (55,511,000)
Proceeds from the sales of rental property 243,244,000 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 3,337,000 9,062,000
Investment in unconsolidated joint ventures (1,266,000) (6,625,000)
Distributions in excess of cumulative earnings from unconsolidated joint ventures 4,571,000 1,689,000
Proceeds from investment receivable   3,625,000
Net cash provided by (used in) investing activities 143,548,000 (422,530,000)
CASH FLOW FROM FINANCING ACTIVITIES    
Borrowings from revolving credit facility 322,000,000 275,000,000
Repayment of revolving credit facility (281,000,000) (471,000,000)
Borrowings from unsecured term loan   325,000,000
Proceeds from mortgages and loans payable 41,090,000 268,642,000
Repayment of mortgages, loans payable and other obligations (277,287,000) (1,430,000)
Issuance of redeemable noncontrolling interests 10,000,000 139,002,000
Payment of financing costs (255,000) (8,627,000)
(Distribution to) contributions from noncontrolling interests   (15,000)
Payment of dividends and distributions (22,830,000) (15,006,000)
Net cash (used in) provided by financing activities (208,282,000) 511,566,000
Net (decrease) increase in cash and cash equivalents (7,835,000) 140,349,000
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] 60,137,000 225,912,000
Mack-Cali Realty LP [Member]    
CASH FLOWS FROM OPERATING ACTIVITIES    
Net income 50,688,000 22,729,000
Adjustments to reconcile net income to net cash provided by Operating activities:    
Depreciation and amortization, including related intangible assets 39,489,000 46,338,000
Amortization of directors deferred compensation stock units 125,000 115,000
Amortization of stock compensation 2,532,000 1,053,000
Amortization of deferred financing costs 1,096,000 1,103,000
Amortization of debt discount and mark-to-market (237,000) 241,000
Write-off of unamortized deferred finance costs related to early extinguishment 105,000  
Equity in (earnings) loss of unconsolidated joint ventures (1,572,000) 51,000
Distributions of cumulative earnings from unconsolidated joint ventures 2,119,000 2,684,000
Realized (gains) losses and unrealized losses on disposition of rental property, net (58,186,000) (5,506,000)
Gain on sale of investments in unconsolidated joint ventures   (12,563,000)
Loss (gain) from extinguishment of debt 10,289,000 239,000
Changes in operating assets and liabilities:    
Increase in unbilled rents receivable, net (3,788,000) (2,950,000)
Increase in deferred charges, goodwill and other assets (1,899,000) (2,842,000)
(Increase) decrease in accounts receivable, net (545,000) 13,000
Increase (decrease) in accounts payable, accrued expenses and other liabilities 14,134,000 (11,396,000)
(Decrease) Increase in rents received in advance and security deposits (2,118,000) 3,891,000
Increase in accrued interest payable 4,667,000 8,113,000
Net cash provided by operating activities 56,899,000 51,313,000
CASH FLOWS FROM INVESTING ACTIVITIES    
Rental property acquisitions and related intangibles (365,000) (413,115,000)
Rental property additions and improvements (55,935,000) (22,471,000)
Development of rental property and other related costs (50,038,000) (55,511,000)
Proceeds from the sales of rental property 243,244,000 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 3,337,000 9,062,000
Investment in unconsolidated joint ventures (1,266,000) (6,625,000)
Distributions in excess of cumulative earnings from unconsolidated joint ventures 4,571,000 1,689,000
Proceeds from investment receivable   3,625,000
Net cash provided by (used in) investing activities 143,548,000 (422,530,000)
CASH FLOW FROM FINANCING ACTIVITIES    
Borrowings from revolving credit facility 322,000,000 275,000,000
Repayment of revolving credit facility (281,000,000) (471,000,000)
Borrowings from unsecured term loan   325,000,000
Proceeds from mortgages and loans payable 41,090,000 268,642,000
Repayment of mortgages, loans payable and other obligations (277,287,000) (1,430,000)
Issuance of redeemable noncontrolling interests 10,000,000 139,002,000
Payment of financing costs (255,000) (8,627,000)
(Distribution to) contributions from noncontrolling interests   (15,000)
Payment of dividends and distributions (22,830,000) (15,006,000)
Net cash (used in) provided by financing activities (208,282,000) 511,566,000
Net (decrease) increase in cash and cash equivalents (7,835,000) 140,349,000
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] $ 60,137,000 $ 225,912,000
[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 $34,830 and $57,596 as of March 31, 2018 and 2017, respectively, pursuant to the adoption of ASU 2016-15..