PROPERTY, FURNITURE AND EQUIPMENT, NET (Details) - PEN (S/)
S/ in Thousands
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Changes in property, plant and equipment [abstract]      
Balance Begining S/ 1,480,702 S/ 1,509,492  
Balance Ending 1,428,173 1,480,702 S/ 1,509,492
Net carrying amount 1,428,173 1,480,702 1,509,492
Land [Member]      
Changes in property, plant and equipment [abstract]      
Balance Ending 401,553    
Net carrying amount 401,553    
Buildings [member]      
Changes in property, plant and equipment [abstract]      
Balance Ending 498,562    
Net carrying amount 498,562    
Installations [member]      
Changes in property, plant and equipment [abstract]      
Balance Ending 175,434    
Net carrying amount 175,434    
Furniture and fixture [Member]      
Changes in property, plant and equipment [abstract]      
Balance Ending 171,728    
Net carrying amount 171,728    
Computer hardware [member]      
Changes in property, plant and equipment [abstract]      
Balance Ending 83,180    
Net carrying amount 83,180    
Vehicles and equipment [member]      
Changes in property, plant and equipment [abstract]      
Balance Ending 28,348    
Net carrying amount 28,348    
Work in progress [member]      
Changes in property, plant and equipment [abstract]      
Balance Ending 69,368    
Net carrying amount 69,368    
Accumulated depreciation      
Changes in property, plant and equipment [abstract]      
Balance Begining 2,092,878 1,994,734 1,857,666
Acquisition of business, Note 2(a) 19,299 0 0
Depreciation for the year 146,066 170,138 178,895
Disposals and others (173,939) (71,994) (41,827)
Balance Ending 2,084,304 2,092,878 1,994,734
Net carrying amount 2,084,304 2,092,878 1,994,734
Accumulated depreciation | Land [Member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 0    
Acquisition of business, Note 2(a) 0    
Depreciation for the year 0    
Disposals and others 0    
Balance Ending 0 0  
Net carrying amount 0 0  
Accumulated depreciation | Buildings [member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 632,261    
Acquisition of business, Note 2(a) 56    
Depreciation for the year 31,065    
Disposals and others (5,692)    
Balance Ending 657,690 632,261  
Net carrying amount 657,690 632,261  
Accumulated depreciation | Installations [member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 457,104    
Depreciation for the year 28,627    
Disposals and others (7,437)    
Balance Ending 478,294 457,104  
Net carrying amount 478,294 457,104  
Accumulated depreciation | Furniture and fixture [Member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 353,458    
Acquisition of business, Note 2(a) 9,678    
Depreciation for the year 33,210    
Disposals and others (88,326)    
Balance Ending 308,020 353,458  
Net carrying amount 308,020 353,458  
Accumulated depreciation | Computer hardware [member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 536,322    
Acquisition of business, Note 2(a) 9,424    
Depreciation for the year 42,378    
Disposals and others (36,101)    
Balance Ending 552,023 536,322  
Net carrying amount 552,023 536,322  
Accumulated depreciation | Vehicles and equipment [member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 113,733    
Acquisition of business, Note 2(a) 141    
Depreciation for the year 10,786    
Disposals and others (36,383)    
Balance Ending 88,277 113,733  
Net carrying amount 88,277 113,733  
Accumulated depreciation | Work in progress [member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 0    
Acquisition of business, Note 2(a) 0    
Depreciation for the year 0    
Disposals and others 0    
Balance Ending 0 0  
Net carrying amount 0 0  
Cost [Member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 3,573,580 3,504,226 3,409,369
Additions 134,776 181,459 143,851
Acquisition of business, Note 2(a) 29,893 0 0
Transfers 0 0 0
Disposals and others (225,772) (112,105) (48,994)
Balance Ending 3,512,477 3,573,580 3,504,226
Net carrying amount 3,512,477 3,573,580 S/ 3,504,226
Cost [Member] | Land [Member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 411,110    
Additions 2,259    
Acquisition of business, Note 2(a) 505    
Transfers 0    
Disposals and others (12,321)    
Balance Ending 401,553 411,110  
Net carrying amount 401,553 411,110  
Cost [Member] | Buildings [member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 1,162,377    
Additions 3,758    
Acquisition of business, Note 2(a) 2,550    
Transfers 2,154    
Disposals and others (14,587)    
Balance Ending 1,156,252 1,162,377  
Net carrying amount 1,156,252 1,162,377  
Cost [Member] | Installations [member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 611,568    
Additions 13,493    
Transfers 39,114    
Disposals and others (10,447)    
Balance Ending 653,728 611,568  
Net carrying amount 653,728 611,568  
Cost [Member] | Furniture and fixture [Member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 521,521    
Additions 29,213    
Acquisition of business, Note 2(a) 14,407    
Transfers 5,549    
Disposals and others (90,942)    
Balance Ending 479,748 521,521  
Net carrying amount 479,748 521,521  
Cost [Member] | Computer hardware [member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 632,214    
Additions 23,094    
Acquisition of business, Note 2(a) 12,121    
Transfers 5,687    
Disposals and others (37,913)    
Balance Ending 635,203 632,214  
Net carrying amount 635,203 632,214  
Cost [Member] | Vehicles and equipment [member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 155,417    
Additions 486    
Acquisition of business, Note 2(a) 310    
Transfers 141    
Disposals and others (39,729)    
Balance Ending 116,625 155,417  
Net carrying amount 116,625 155,417  
Cost [Member] | Work in progress [member]      
Changes in property, plant and equipment [abstract]      
Balance Begining 79,373    
Additions 62,473    
Acquisition of business, Note 2(a) 0    
Transfers (52,645)    
Disposals and others (19,833)    
Balance Ending 69,368 79,373  
Net carrying amount S/ 69,368 S/ 79,373