Loans - Amortized cost basis and interest income recognized on non-accrual loans (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	$ 137,309	$ 125,958
Non-accrual with allowance	224,089	231,653
Construction
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance		0
Non-accrual with allowance		6,378
Mortgages
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	68,454	84,797
Non-accrual with allowance	117,900	101,500
Commercial | Commercial multi-family
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	8,700	0
Non-accrual with allowance	87	1,991
Commercial | CRE non-owner occupied
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	4,846	3,695
Non-accrual with allowance	4,929	6,167
Commercial | CRE owner occupied
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	40,118	24,309
Non-accrual with allowance	8,730	11,395
Commercial | Commercial and Industrial
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	9,020	6,991
Non-accrual with allowance	15,865	29,607
Leasing
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	445	481
Non-accrual with allowance	6,922	8,151
Consumer | Home equity lines of credit
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	0	0
Non-accrual with allowance	3,834	3,733
Consumer | Personal loans
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	3,649	3,589
Non-accrual with allowance	19,180	18,247
Consumer | Auto Loan
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	2,077	1,833
Non-accrual with allowance	45,751	43,782
Consumer | Other
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	0	263
Non-accrual with allowance	891	702
Puerto Rico
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	104,823	121,961
Non-accrual with allowance	183,992	206,757
Puerto Rico | Construction
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance		0
Non-accrual with allowance		6,378
Puerto Rico | Mortgages
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	68,248	84,677
Non-accrual with allowance	89,672	90,429
Puerto Rico | Commercial | Commercial multi-family
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	0	0
Non-accrual with allowance	87	1,991
Puerto Rico | Commercial | CRE non-owner occupied
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	3,514	3,695
Non-accrual with allowance	3,979	5,050
Puerto Rico | Commercial | CRE owner occupied
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	17,870	20,432
Non-accrual with allowance	8,730	8,998
Puerto Rico | Commercial | Commercial and Industrial
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	9,020	6,991
Non-accrual with allowance	10,619	25,835
Puerto Rico | Leasing
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	445	481
Non-accrual with allowance	6,922	8,151
Puerto Rico | Consumer | Home equity lines of credit
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	0	0
Non-accrual with allowance	0	0
Puerto Rico | Consumer | Personal loans
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	3,649	3,589
Non-accrual with allowance	17,343	15,442
Puerto Rico | Consumer | Auto Loan
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	2,077	1,833
Non-accrual with allowance	45,751	43,782
Puerto Rico | Consumer | Other
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	0	263
Non-accrual with allowance	889	701
Popular U.S.
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	32,486	3,997
Non-accrual with allowance	40,097	24,896
Popular U.S. | Construction
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance		0
Non-accrual with allowance		0
Popular U.S. | Mortgages
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	206	120
Non-accrual with allowance	28,228	11,071
Popular U.S. | Commercial | Commercial multi-family
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	8,700	0
Non-accrual with allowance	0	0
Popular U.S. | Commercial | CRE non-owner occupied
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	1,332	0
Non-accrual with allowance	950	1,117
Popular U.S. | Commercial | CRE owner occupied
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	22,248	3,877
Non-accrual with allowance	0	2,397
Popular U.S. | Commercial | Commercial and Industrial
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	0	0
Non-accrual with allowance	5,246	3,772
Popular U.S. | Leasing
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	0	0
Non-accrual with allowance	0	0
Popular U.S. | Consumer | Home equity lines of credit
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	0	0
Non-accrual with allowance	3,834	3,733
Popular U.S. | Consumer | Personal loans
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	0	0
Non-accrual with allowance	1,837	2,805
Popular U.S. | Consumer | Auto Loan
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	0	0
Non-accrual with allowance	0	0
Popular U.S. | Consumer | Other
Financing receivable nonaccrual status [Line Items]
Non-accrual with no allowance	0	0
Non-accrual with allowance	$ 2	$ 1