Segment reporting - Selected Balance Sheet information (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Segment Reporting Information [Line Items]
Assets	$ 71,323,074	$ 70,758,155	$ 69,736,936
Deposits	63,668,501	63,618,243
Puerto Rico
Segment Reporting Information [Line Items]
Assets	54,200,914	54,181,300
Loans	23,672,112	22,519,961
Deposits	50,759,657	51,282,007
Popular U.S.
Segment Reporting Information [Line Items]
Assets	15,883,947	15,343,156
Loans	11,998,043	12,006,012
Deposits	11,203,741	10,643,602
Other
Segment Reporting Information [Line Items]
Assets	1,238,213	1,233,699
Loans	530,321	543,299
Deposits	$ 1,705,103	$ 1,692,634