NET GAIN ON SECURITIES - Additional Information (Details) - Associates [member] - PEN (S/)
S/ in Thousands
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Gains (losses) on disposals of investments [1] S/ 79,844 S/ 72,254 S/ 49,268
Entidad Prestadora de Salud [Member]      
Gains (losses) on disposals of investments S/ 53,600 S/ 50,400  
[1] It mainly includes the gain of its associated “Entidad Prestadora de Salud” for approximately S/53.6 million during the year 2019 (S/50.4 million during the year 2018).