Senior Unsecured Notes (Tables) - Unsecured Note [Member]
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3 Months Ended | 
Mar. 31, 2017  | 
| Debt Instrument [Line Items] | 
 
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| Summary Of Senior Unsecured Notes | 
 
		
			
		 
		
			
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						March 31, 
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						December 31, 
				 | 
				
					 
						  
				 | 
				
					 
						Effective  
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				 | 
			 
			
				| 
					 
						 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						2017 
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				 | 
				
					 
						  
				 | 
				
					 
						2016 
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				 | 
				
					 
						Rate (1) 
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				 | 
			 
			
				| 
					 
						2.500% Senior Unsecured Notes, due  December 15, 2017 
				 | 
				
					 
						  
				 | 
				
					 
						$ 
				 | 
				250,000 
				 | 
				
					 
						  
				 | 
				
					 
						$ 
				 | 
				250,000 
				 | 
				
					 
						  
				 | 
				2.803 
				 | 
				
					 
						% 
				 | 
			 
			
				| 
					 
						4.500% Senior Unsecured Notes, due April 18, 2022 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				300,000 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				300,000 
				 | 
				
					 
						  
				 | 
				4.612 
				 | 
				
					 
						% 
				 | 
			 
			
				| 
					 
						3.150% Senior Unsecured Notes, due May 15, 2023 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				275,000 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				275,000 
				 | 
				
					 
						  
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				3.517 
				 | 
				
					 
						% 
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				| 
					 
						Principal balance outstanding 
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				 | 
				
					 
						  
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				825,000 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				825,000 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
			 
			
				| 
					 
						Adjustment for unamortized debt discount 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				(4,190)
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				(4,430)
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
			 
			
				| 
					 
						Unamortized deferred financing costs 
				 | 
				
					 
						  
				 | 
				
					 
						  
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				(2,986)
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				 | 
				
					 
						  
				 | 
				(3,215)
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				| 
					 
						Total senior unsecured notes, net 
				 | 
				
					 
						  
				 | 
				
					 
						$ 
				 | 
				817,824 
				 | 
				
					 
						  
				 | 
				
					 
						$ 
				 | 
				817,355 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
			 
		  
		
			
		 
		
			(1)Includes the cost of terminated treasury lock agreements (if any), offering and other transaction costs and the discount/premium on the notes, as applicable.
		 
		
			
		 
		  
	   
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| Mack-Cali Realty LP [Member] | 
 
 | 
| Debt Instrument [Line Items] | 
 
 | 
| Summary Of Senior Unsecured Notes | 
 
		
			
		 
		
			
				| 
					 
						 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
			 
			
				| 
					 
						 
				 | 
				
					 
						  
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				 | 
				
					 
						  
				 | 
				
					 
						  
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				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
			 
			
				| 
					 
						 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						March 31, 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						December 31, 
				 | 
				
					 
						  
				 | 
				
					 
						Effective  
				 | 
				
					 
						  
				 | 
			 
			
				| 
					 
						 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						2017 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						2016 
				 | 
				
					 
						  
				 | 
				
					 
						Rate (1) 
				 | 
				
					 
						  
				 | 
			 
			
				| 
					 
						2.500% Senior Unsecured Notes, due  December 15, 2017 
				 | 
				
					 
						  
				 | 
				
					 
						$ 
				 | 
				250,000 
				 | 
				
					 
						  
				 | 
				
					 
						$ 
				 | 
				250,000 
				 | 
				
					 
						  
				 | 
				2.803 
				 | 
				
					 
						% 
				 | 
			 
			
				| 
					 
						4.500% Senior Unsecured Notes, due April 18, 2022 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				300,000 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				300,000 
				 | 
				
					 
						  
				 | 
				4.612 
				 | 
				
					 
						% 
				 | 
			 
			
				| 
					 
						3.150% Senior Unsecured Notes, due May 15, 2023 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				275,000 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				275,000 
				 | 
				
					 
						  
				 | 
				3.517 
				 | 
				
					 
						% 
				 | 
			 
			
				| 
					 
						Principal balance outstanding 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				825,000 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				825,000 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
			 
			
				| 
					 
						Adjustment for unamortized debt discount 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				(4,190)
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				(4,430)
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
			 
			
				| 
					 
						Unamortized deferred financing costs 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				(2,986)
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				(3,215)
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
			 
			
				| 
					 
						 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
			 
			
				| 
					 
						Total senior unsecured notes, net 
				 | 
				
					 
						  
				 | 
				
					 
						$ 
				 | 
				817,824 
				 | 
				
					 
						  
				 | 
				
					 
						$ 
				 | 
				817,355 
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
				
					 
						  
				 | 
			 
		  
		
			
		 
		
			(1)Includes the cost of terminated treasury lock agreements (if any), offering and other transaction costs and the discount/premium on the notes, as applicable.
		 
		
			
		 
		  
	   
 |