Loans - Amortized cost basis and interest income recognized on non-accrual loans (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Financing receivable nonaccrual status
Non-accrual with no allowance	$ 280,471	$ 203,460
Non-accrual with allowance	404,712	534,314
Construction
Financing receivable nonaccrual status
Non-accrual with no allowance	14,877	0
Non-accrual with allowance	0	29,057
Mortgages
Financing receivable nonaccrual status
Non-accrual with no allowance	184,388	142,254
Non-accrual with allowance	199,588	286,953
Commercial | Commercial multi-family
Financing receivable nonaccrual status
Non-accrual with no allowance	5,949	0
Non-accrual with allowance	397	2,399
Commercial | CRE non-owner occupied
Financing receivable nonaccrual status
Non-accrual with no allowance	30,253	35,968
Non-accrual with allowance	42,499	41,838
Commercial | CRE owner occupied
Financing receivable nonaccrual status
Non-accrual with no allowance	18,338	14,825
Non-accrual with allowance	61,663	77,510
Commercial | Commercial and Industrial
Financing receivable nonaccrual status
Non-accrual with no allowance	19,082	1,148
Non-accrual with allowance	47,384	36,392
Leasing
Financing receivable nonaccrual status
Non-accrual with no allowance	123	0
Non-accrual with allowance	2,163	3,441
Consumer | Home equity lines of credit
Financing receivable nonaccrual status
Non-accrual with no allowance	0	0
Non-accrual with allowance	6,377	7,491
Consumer | Personal loans
Financing receivable nonaccrual status
Non-accrual with no allowance	6,928	9,265
Non-accrual with allowance	17,765	18,596
Consumer | Auto Loan
Financing receivable nonaccrual status
Non-accrual with no allowance	533	0
Non-accrual with allowance	12,753	15,736
Consumer | Other
Financing receivable nonaccrual status
Non-accrual with no allowance	0	0
Non-accrual with allowance	14,123	14,901
Puerto Rico
Financing receivable nonaccrual status
Non-accrual with no allowance	274,172	202,943
Non-accrual with allowance	382,617	497,434
Puerto Rico | Construction
Financing receivable nonaccrual status
Non-accrual with no allowance	14,877	0
Non-accrual with allowance	0	21,497
Puerto Rico | Mortgages
Financing receivable nonaccrual status
Non-accrual with no allowance	184,038	141,737
Non-accrual with allowance	186,615	272,606
Puerto Rico | Commercial | Commercial multi-family
Financing receivable nonaccrual status
Non-accrual with no allowance	0	0
Non-accrual with allowance	397	505
Puerto Rico | Commercial | CRE non-owner occupied
Financing receivable nonaccrual status
Non-accrual with no allowance	30,253	35,968
Non-accrual with allowance	42,125	41,169
Puerto Rico | Commercial | CRE owner occupied
Financing receivable nonaccrual status
Non-accrual with no allowance	18,338	14,825
Non-accrual with allowance	61,470	77,176
Puerto Rico | Commercial | Commercial and Industrial
Financing receivable nonaccrual status
Non-accrual with no allowance	19,082	1,148
Non-accrual with allowance	46,038	33,301
Puerto Rico | Leasing
Financing receivable nonaccrual status
Non-accrual with no allowance	123	0
Non-accrual with allowance	2,163	3,441
Puerto Rico | Consumer | Home equity lines of credit
Financing receivable nonaccrual status
Non-accrual with no allowance	0	0
Non-accrual with allowance	0	0
Puerto Rico | Consumer | Personal loans
Financing receivable nonaccrual status
Non-accrual with no allowance	6,928	9,265
Non-accrual with allowance	16,933	17,122
Puerto Rico | Consumer | Auto Loan
Financing receivable nonaccrual status
Non-accrual with no allowance	533	0
Non-accrual with allowance	12,753	15,736
Puerto Rico | Consumer | Other
Financing receivable nonaccrual status
Non-accrual with no allowance	0	0
Non-accrual with allowance	14,123	14,881
Popular U.S.
Financing receivable nonaccrual status
Non-accrual with no allowance	6,299	517
Non-accrual with allowance	22,095	36,880
Popular U.S. | Construction
Financing receivable nonaccrual status
Non-accrual with no allowance	0	0
Non-accrual with allowance	0	7,560
Popular U.S. | Mortgages
Financing receivable nonaccrual status
Non-accrual with no allowance	350	517
Non-accrual with allowance	12,973	14,347
Popular U.S. | Commercial | Commercial multi-family
Financing receivable nonaccrual status
Non-accrual with no allowance	5,949	0
Non-accrual with allowance	0	1,894
Popular U.S. | Commercial | CRE non-owner occupied
Financing receivable nonaccrual status
Non-accrual with no allowance	0	0
Non-accrual with allowance	374	669
Popular U.S. | Commercial | CRE owner occupied
Financing receivable nonaccrual status
Non-accrual with no allowance	0	0
Non-accrual with allowance	193	334
Popular U.S. | Commercial | Commercial and Industrial
Financing receivable nonaccrual status
Non-accrual with no allowance	0	0
Non-accrual with allowance	1,346	3,091
Popular U.S. | Leasing
Financing receivable nonaccrual status
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
Non-accrual with no allowance	0	0
Non-accrual with allowance	6,377	7,491
Popular U.S. | Consumer | Personal loans
Financing receivable nonaccrual status
Non-accrual with no allowance	0	0
Non-accrual with allowance	832	1,474
Popular U.S. | Consumer | Auto Loan
Financing receivable nonaccrual status
Non-accrual with no allowance	0	0
Non-accrual with allowance	0	0
Popular U.S. | Consumer | Other
Financing receivable nonaccrual status
Non-accrual with no allowance	0	0
Non-accrual with allowance	$ 0	$ 20