OTHER ASSETS AND OTHER LIABILITIES - Additional Information (Details) - PEN (S/)
S/ in Thousands
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Disclosure of Other Assets And Other Liabilities [Line Items]      
Gains (losses) on cash flow hedges, net of tax S/ (62,002) S/ 73,263 S/ (59,709)
Investments in associates 628,822 582,132  
impairment net carrying amount 300 1,100  
Property, plant and equipment 1,428,173 1,480,702 S/ 1,509,492
Investment property [member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Property, plant and equipment 937,800 805,200  
Land and buildings [member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Disposals, investment property   5,000  
Land [Member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Additions from acquisitions, investment property 1,300    
Property, plant and equipment 401,553    
Buildings [member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Additions from acquisitions, investment property 8,800    
Property, plant and equipment 498,562    
Entidad Prestadora de Salud [Member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Investments in associates 571,900 537,200  
Revoked hedges [Member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Gains (losses) on cash flow hedges, net of tax 100 4,600  
Cash flow hedges      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Gains (losses) on cash flow hedges, net of tax 3,800 7,800  
Lurin [Member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Additions from acquisitions, investment property   21,900  
Chinchon Gallery [Member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Additions from acquisitions, investment property   3,900  
Trujillo [Member] | Plot 1 and 2 [Member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Additions from acquisitions, investment property   9,500  
Av Reducto [Member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Disposals, investment property   10,100  
Av Reducto [Member] | Land [Member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Disposals, investment property   6,500  
Av Salaverry [Member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Disposals, investment property   2,900  
Av Salaverry [Member] | Land [Member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Disposals, investment property   2,000  
Av Santa Cruz [Member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Disposals, investment property   12,600  
Edificio Panorama [Member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Additions from acquisitions, investment property   S/ 10,000  
Santiago de Surco      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Additions from acquisitions, investment property 10,100    
San Martn de Porres      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Additions from acquisitions, investment property 8,700    
San Isidro      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Disposals, investment property 27,500    
San Isidro | Buildings [member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Disposals, investment property 6,300    
Chiclayo      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Disposals, investment property 3,400    
Chiclayo | Buildings [member]      
Disclosure of Other Assets And Other Liabilities [Line Items]      
Disposals, investment property S/ 4,200