Consolidated Statements Of Cash Flows - USD ($)
 3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES    
Net income $ 275,594,000 $ 50,688,000
Adjustments to reconcile net income (loss) to net cash provided by Operating activities:    
Depreciation and amortization, including related intangible assets 47,294,000 39,489,000
Amortization of directors deferred compensation stock units 130,000 125,000
Amortization of stock compensation 1,880,000 2,532,000
Amortization of deferred financing costs 1,189,000 1,096,000
Amortization of debt discount and mark-to-market (237,000) (237,000)
Write off of unamortized deferred finance costs related to early extinguishment   105,000
Equity in (earnings) loss of unconsolidated joint ventures 681,000 (1,572,000)
Distributions of cumulative earnings from unconsolidated joint ventures 1,553,000 2,119,000
Gain on change of control of interests (13,790,000)  
Realized (gains) losses and unrealized losses on disposition of rental property, net (268,109,000) (58,186,000)
Gain on sale of investments in unconsolidated joint ventures (903,000)  
(Gain)Loss from extinguishment of debt (1,311,000) 10,289,000
Changes in operating assets and liabilities:    
Increase in unbilled rents receivable, net (2,789,000) (3,788,000)
Increase in deferred charges, goodwill and other assets (6,774,000) (1,899,000)
Increase in accounts receivable, net (1,830,000) (545,000)
Increase in accounts payable, accrued expenses and other liabilities 15,942,000 14,134,000
Decrease in rents received in advance and security deposits (7,784,000) (2,118,000)
Increase in accrued interest payable 5,301,000 4,667,000
Net cash provided by operating activities 46,037,000 56,899,000
CASH FLOWS FROM INVESTING ACTIVITIES    
Rental property acquisitions and related intangibles (222,893,000) (365,000)
Rental property additions and improvements (43,307,000) (55,935,000)
Development of rental property and other related costs (38,568,000) (50,038,000)
Proceeds from the sales of rental property 330,369,000 243,244,000
Proceeds from the sale of investments in unconsolidated joint ventures 4,039,000  
Repayment of notes receivable 125,000 3,337,000
Investment in unconsolidated joint ventures (2,443,000) (1,266,000)
Distributions in excess of cumulative earnings from unconsolidated joint ventures 1,566,000 4,571,000
Net cash provided by investing activities 28,888,000 143,548,000
CASH FLOW FROM FINANCING ACTIVITIES    
Borrowings from revolving credit facility 92,000,000 322,000,000
Repayment of revolving credit facility (204,000,000) (281,000,000)
Repayment of unsecured term loan (90,000,000)  
Proceeds from mortgages and loans payable 121,537,000 41,090,000
Repayment of mortgages, loans payable and other obligations (25,183,000) (277,287,000)
Acquisition of noncontrolling interests (5,017,000)  
Issuance of redeemable noncontrolling interests, net 45,000,000 10,000,000
Payment of financing costs (1,363,000) (255,000)
Distributions to noncontrolling interests (99,000)  
Payment of dividends and distributions (24,732,000) (22,830,000)
Net cash used in financing activities (91,857,000) (208,282,000)
Net decrease in cash and cash equivalents (16,932,000) (7,835,000)
Cash, cash equivalents and restricted cash, beginning of period [1] 49,554,000 67,972,000
Cash, cash equivalents and restricted cash, end of period [2] 32,622,000 60,137,000
Mack-Cali Realty LP [Member]    
CASH FLOWS FROM OPERATING ACTIVITIES    
Net income 275,594,000 50,688,000
Adjustments to reconcile net income (loss) to net cash provided by Operating activities:    
Depreciation and amortization, including related intangible assets 47,294,000 39,489,000
Amortization of directors deferred compensation stock units 130,000 125,000
Amortization of stock compensation 1,880,000 2,532,000
Amortization of deferred financing costs 1,189,000 1,096,000
Amortization of debt discount and mark-to-market (237,000) (237,000)
Write off of unamortized deferred finance costs related to early extinguishment   105,000
Equity in (earnings) loss of unconsolidated joint ventures 681,000 (1,572,000)
Distributions of cumulative earnings from unconsolidated joint ventures 1,553,000 2,119,000
Gain on change of control of interests (13,790,000)  
Realized (gains) losses and unrealized losses on disposition of rental property, net (268,109,000) (58,186,000)
Gain on sale of investments in unconsolidated joint ventures (903,000)  
(Gain)Loss from extinguishment of debt (1,311,000) 10,289,000
Changes in operating assets and liabilities:    
Increase in unbilled rents receivable, net (2,789,000) (3,788,000)
Increase in deferred charges, goodwill and other assets (6,774,000) (1,899,000)
Increase in accounts receivable, net (1,830,000) (545,000)
Increase in accounts payable, accrued expenses and other liabilities 15,942,000 14,134,000
Decrease in rents received in advance and security deposits (7,784,000) (2,118,000)
Increase in accrued interest payable 5,301,000 4,667,000
Net cash provided by operating activities 46,037,000 56,899,000
CASH FLOWS FROM INVESTING ACTIVITIES    
Rental property acquisitions and related intangibles (222,893,000) (365,000)
Rental property additions and improvements (43,307,000) (55,935,000)
Development of rental property and other related costs (38,568,000) (50,038,000)
Proceeds from the sales of rental property 330,369,000 243,244,000
Proceeds from the sale of investments in unconsolidated joint ventures 4,039,000  
Repayment of notes receivable 125,000 3,337,000
Investment in unconsolidated joint ventures (2,443,000) (1,266,000)
Distributions in excess of cumulative earnings from unconsolidated joint ventures 1,566,000 4,571,000
Net cash provided by investing activities 28,888,000 143,548,000
CASH FLOW FROM FINANCING ACTIVITIES    
Borrowings from revolving credit facility 92,000,000 322,000,000
Repayment of revolving credit facility (204,000,000) (281,000,000)
Repayment of unsecured term loan (90,000,000)  
Proceeds from mortgages and loans payable 121,537,000 41,090,000
Repayment of mortgages, loans payable and other obligations (25,183,000) (277,287,000)
Acquisition of noncontrolling interests (5,017,000)  
Issuance of redeemable noncontrolling interests, net 45,000,000 10,000,000
Payment of financing costs (1,363,000) (255,000)
Distributions to noncontrolling interests (99,000)  
Payment of dividends and distributions (24,732,000) (22,830,000)
Net cash used in financing activities (91,857,000) (208,282,000)
Net decrease in cash and cash equivalents (16,932,000) (7,835,000)
Cash, cash equivalents and restricted cash, beginning of period [1] 49,554,000 67,972,000
Cash, cash equivalents and restricted cash, end of period [2] $ 32,622,000 $ 60,137,000
[1] Includes Restricted Cash of $19,921 and $39,792 as of December 31, 2018 and 2017, respectively.
[2] Includes Restricted Cash of $20,561 and $34,830 as of March 31, 2019 and 2018, respectively.