Loans - Loans held-in-portfolio in past due status, non-performing status and accruing loans past-due 90 days or more by loan class (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financing Receivable, Recorded Investment, Past Due
Past Due	$ 1,632,322	$ 2,269,553
Current	27,223,050	27,115,643
Loans held in portfolio, net of unearned income	28,855,372	29,385,196
Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	301,198	361,661
Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	148,504	142,054
Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	1,182,620	1,765,838
Non-accrual loans	632,835	737,774
Accruing loans past-due 90 days or more	549,785	1,028,064
Construction
Financing Receivable, Recorded Investment, Past Due
Past Due	29,855	50,369
Current	771,185	875,839
Loans held in portfolio, net of unearned income	801,040	926,208
Construction \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	14,978	21,312
Construction \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	0
Construction \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	14,877	29,057
Non-accrual loans	14,877	29,057
Accruing loans past-due 90 days or more	0	0
Mortgages
Financing Receivable, Recorded Investment, Past Due
Past Due	1,189,198	1,775,902
Current	6,349,954	6,114,778
Loans held in portfolio, net of unearned income	7,539,152	7,890,680
Mortgages \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	199,324	229,024
Mortgages \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	79,178	103,190
Mortgages \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	910,696	1,443,688
Non-accrual loans	369,043	429,207
Accruing loans past-due 90 days or more	541,653	1,014,481
Commercial \| Commercial multi-family
Financing Receivable, Recorded Investment, Past Due
Past Due	22,959	8,468
Current	1,859,147	1,887,523
Loans held in portfolio, net of unearned income	1,882,106	1,895,991
Commercial \| Commercial multi-family \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	392	6,069
Commercial \| Commercial multi-family \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	22,171	0
Commercial \| Commercial multi-family \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	396	2,399
Non-accrual loans	396	2,399
Accruing loans past-due 90 days or more	0	0
Commercial \| CRE non-owner occupied
Financing Receivable, Recorded Investment, Past Due
Past Due	85,762	88,062
Current	4,297,955	3,913,081
Loans held in portfolio, net of unearned income	4,383,717	4,001,143
Commercial \| CRE non-owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	3,230	3,113
Commercial \| CRE non-owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	22,015	7,143
Commercial \| CRE non-owner occupied \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	60,517	77,806
Non-accrual loans	60,517	77,806
Accruing loans past-due 90 days or more	0	0
Commercial \| CRE owner occupied
Financing Receivable, Recorded Investment, Past Due
Past Due	77,340	102,664
Current	1,737,933	1,840,611
Loans held in portfolio, net of unearned income	1,815,273	1,943,275
Commercial \| CRE owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	3,877	8,461
Commercial \| CRE owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	614	1,868
Commercial \| CRE owner occupied \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	72,849	92,335
Non-accrual loans	72,849	92,335
Accruing loans past-due 90 days or more	0	0
Commercial \| Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Past Due	55,906	50,290
Current	5,166,669	5,723,611
Loans held in portfolio, net of unearned income	5,222,575	5,773,901
Commercial \| Commercial and Industrial \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	2,445	11,340
Commercial \| Commercial and Industrial \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	577	847
Commercial \| Commercial and Industrial \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	52,884	38,103
Non-accrual loans	52,419	37,540
Accruing loans past-due 90 days or more	465	563
Leasing
Financing Receivable, Recorded Investment, Past Due
Past Due	12,704	14,009
Current	1,335,975	1,183,652
Loans held in portfolio, net of unearned income	1,348,679	1,197,661
Leasing \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	8,193	9,141
Leasing \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	1,969	1,427
Leasing \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	2,542	3,441
Non-accrual loans	2,542	3,441
Accruing loans past-due 90 days or more	0	0
Consumer \| Credit card
Financing Receivable, Recorded Investment, Past Due
Past Due	16,436	23,970
Current	870,165	895,996
Loans held in portfolio, net of unearned income	886,601	919,966
Consumer \| Credit card \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	5,211	6,550
Consumer \| Credit card \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	3,667	4,619
Consumer \| Credit card \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	7,558	12,801
Non-accrual loans	0	0
Accruing loans past-due 90 days or more	7,558	12,801
Consumer \| Home equity lines of credit
Financing Receivable, Recorded Investment, Past Due
Past Due	6,753	8,301
Current	76,549	90,449
Loans held in portfolio, net of unearned income	83,302	98,750
Consumer \| Home equity lines of credit \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	736	420
Consumer \| Home equity lines of credit \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	76	342
Consumer \| Home equity lines of credit \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	5,941	7,539
Non-accrual loans	5,941	7,491
Accruing loans past-due 90 days or more	0	48
Consumer \| Personal loans
Financing Receivable, Recorded Investment, Past Due
Past Due	38,809	50,041
Current	1,350,046	1,426,944
Loans held in portfolio, net of unearned income	1,388,855	1,476,985
Consumer \| Personal loans \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	9,917	12,741
Consumer \| Personal loans \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,498	9,439
Consumer \| Personal loans \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	22,394	27,861
Non-accrual loans	22,394	27,861
Accruing loans past-due 90 days or more	0	0
Consumer \| Auto Loan
Financing Receivable, Recorded Investment, Past Due
Past Due	81,494	81,618
Current	3,295,200	3,050,610
Loans held in portfolio, net of unearned income	3,376,694	3,132,228
Consumer \| Auto Loan \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	52,486	53,186
Consumer \| Auto Loan \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	11,663	12,696
Consumer \| Auto Loan \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	17,345	15,736
Non-accrual loans	17,345	15,736
Accruing loans past-due 90 days or more	0	0
Consumer \| Other
Financing Receivable, Recorded Investment, Past Due
Past Due	15,106	15,859
Current	112,272	112,549
Loans held in portfolio, net of unearned income	127,378	128,408
Consumer \| Other \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	409	304
Consumer \| Other \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	76	483
Consumer \| Other \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	14,621	15,072
Non-accrual loans	14,512	14,901
Accruing loans past-due 90 days or more	109	171
Puerto Rico
Financing Receivable, Recorded Investment, Past Due
Past Due	1,555,928	2,146,682
Current	19,599,753	19,426,598
Loans held in portfolio, net of unearned income	21,155,681	21,573,280
Puerto Rico \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	279,026	297,700
Puerto Rico \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	118,247	120,544
Puerto Rico \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	1,158,655	1,728,438
Non-accrual loans	608,871	700,377
Accruing loans past-due 90 days or more	549,784	1,028,061
Puerto Rico \| Construction
Financing Receivable, Recorded Investment, Past Due
Past Due	14,877	21,497
Current	112,602	135,609
Loans held in portfolio, net of unearned income	127,479	157,106
Puerto Rico \| Construction \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	0
Puerto Rico \| Construction \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	0
Puerto Rico \| Construction \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	14,877	21,497
Non-accrual loans	14,877	21,497
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Mortgages
Financing Receivable, Recorded Investment, Past Due
Past Due	1,170,508	1,712,152
Current	5,204,541	5,057,991
Loans held in portfolio, net of unearned income	6,375,049	6,770,143
Puerto Rico \| Mortgages \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	197,955	195,602
Puerto Rico \| Mortgages \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	76,345	87,726
Puerto Rico \| Mortgages \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	896,208	1,428,824
Non-accrual loans	354,555	414,343
Accruing loans past-due 90 days or more	541,653	1,014,481
Puerto Rico \| Commercial \| Commercial multi-family
Financing Receivable, Recorded Investment, Past Due
Past Due	788	1,301
Current	149,639	150,979
Loans held in portfolio, net of unearned income	150,427	152,280
Puerto Rico \| Commercial \| Commercial multi-family \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	392	796
Puerto Rico \| Commercial \| Commercial multi-family \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	0
Puerto Rico \| Commercial \| Commercial multi-family \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	396	505
Non-accrual loans	396	505
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Commercial \| CRE non-owner occupied
Financing Receivable, Recorded Investment, Past Due
Past Due	78,187	82,829
Current	2,268,441	1,924,504
Loans held in portfolio, net of unearned income	2,346,628	2,007,333
Puerto Rico \| Commercial \| CRE non-owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	661	2,189
Puerto Rico \| Commercial \| CRE non-owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	17,383	3,503
Puerto Rico \| Commercial \| CRE non-owner occupied \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	60,143	77,137
Non-accrual loans	60,143	77,137
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Commercial \| CRE owner occupied
Financing Receivable, Recorded Investment, Past Due
Past Due	75,196	101,489
Current	1,394,503	1,497,406
Loans held in portfolio, net of unearned income	1,469,699	1,598,895
Puerto Rico \| Commercial \| CRE owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	2,719	8,270
Puerto Rico \| Commercial \| CRE owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	614	1,218
Puerto Rico \| Commercial \| CRE owner occupied \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	71,863	92,001
Non-accrual loans	71,863	92,001
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Commercial \| Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Past Due	53,673	46,010
Current	3,618,266	4,183,098
Loans held in portfolio, net of unearned income	3,671,939	4,229,108
Puerto Rico \| Commercial \| Commercial and Industrial \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	1,641	10,223
Puerto Rico \| Commercial \| Commercial and Industrial \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	576	775
Puerto Rico \| Commercial \| Commercial and Industrial \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	51,456	35,012
Non-accrual loans	50,992	34,449
Accruing loans past-due 90 days or more	464	563
Puerto Rico \| Leasing
Financing Receivable, Recorded Investment, Past Due
Past Due	12,704	14,009
Current	1,335,975	1,183,652
Loans held in portfolio, net of unearned income	1,348,679	1,197,661
Puerto Rico \| Leasing \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	8,193	9,141
Puerto Rico \| Leasing \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	1,969	1,427
Puerto Rico \| Leasing \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	2,542	3,441
Non-accrual loans	2,542	3,441
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Consumer \| Credit card
Financing Receivable, Recorded Investment, Past Due
Past Due	16,436	23,967
Current	870,139	895,968
Loans held in portfolio, net of unearned income	886,575	919,935
Puerto Rico \| Consumer \| Credit card \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	5,211	6,550
Puerto Rico \| Consumer \| Credit card \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	3,667	4,619
Puerto Rico \| Consumer \| Credit card \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	7,558	12,798
Non-accrual loans	0	0
Accruing loans past-due 90 days or more	7,558	12,798
Puerto Rico \| Consumer \| Home equity lines of credit
Financing Receivable, Recorded Investment, Past Due
Past Due	46	232
Current	3,507	3,947
Loans held in portfolio, net of unearned income	3,553	4,179
Puerto Rico \| Consumer \| Home equity lines of credit \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	46	184
Puerto Rico \| Consumer \| Home equity lines of credit \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	0
Puerto Rico \| Consumer \| Home equity lines of credit \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	0	48
Non-accrual loans	0	0
Accruing loans past-due 90 days or more	0	48
Puerto Rico \| Consumer \| Personal loans
Financing Receivable, Recorded Investment, Past Due
Past Due	36,929	45,739
Current	1,238,448	1,232,008
Loans held in portfolio, net of unearned income	1,275,377	1,277,747
Puerto Rico \| Consumer \| Personal loans \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	9,329	11,255
Puerto Rico \| Consumer \| Personal loans \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	5,954	8,097
Puerto Rico \| Consumer \| Personal loans \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	21,646	26,387
Non-accrual loans	21,646	26,387
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Consumer \| Auto Loan
Financing Receivable, Recorded Investment, Past Due
Past Due	81,494	81,618
Current	3,295,200	3,050,610
Loans held in portfolio, net of unearned income	3,376,694	3,132,228
Puerto Rico \| Consumer \| Auto Loan \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	52,486	53,186
Puerto Rico \| Consumer \| Auto Loan \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	11,663	12,696
Puerto Rico \| Consumer \| Auto Loan \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	17,345	15,736
Non-accrual loans	17,345	15,736
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Consumer \| Other
Financing Receivable, Recorded Investment, Past Due
Past Due	15,090	15,839
Current	108,492	110,826
Loans held in portfolio, net of unearned income	123,582	126,665
Puerto Rico \| Consumer \| Other \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	393	304
Puerto Rico \| Consumer \| Other \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	76	483
Puerto Rico \| Consumer \| Other \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	14,621	15,052
Non-accrual loans	14,512	14,881
Accruing loans past-due 90 days or more	109	171
Popular U.S.
Financing Receivable, Recorded Investment, Past Due
Past Due	76,394	122,871
Current	7,623,297	7,689,045
Loans held in portfolio, net of unearned income	7,699,691	7,811,916
Popular U.S. \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	22,172	63,961
Popular U.S. \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	30,257	21,510
Popular U.S. \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	23,965	37,400
Non-accrual loans	23,964	37,397
Accruing loans past-due 90 days or more	1	3
Popular U.S. \| Construction
Financing Receivable, Recorded Investment, Past Due
Past Due	14,978	28,872
Current	658,583	740,230
Loans held in portfolio, net of unearned income	673,561	769,102
Popular U.S. \| Construction \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	14,978	21,312
Popular U.S. \| Construction \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	0
Popular U.S. \| Construction \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	0	7,560
Non-accrual loans	0	7,560
Accruing loans past-due 90 days or more	0	0
Popular U.S. \| Mortgages
Financing Receivable, Recorded Investment, Past Due
Past Due	18,690	63,750
Current	1,145,413	1,056,787
Loans held in portfolio, net of unearned income	1,164,103	1,120,537
Popular U.S. \| Mortgages \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	1,369	33,422
Popular U.S. \| Mortgages \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	2,833	15,464
Popular U.S. \| Mortgages \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	14,488	14,864
Non-accrual loans	14,488	14,864
Accruing loans past-due 90 days or more	0	0
Popular U.S. \| Commercial \| Commercial multi-family
Financing Receivable, Recorded Investment, Past Due
Past Due	22,171	7,167
Current	1,709,508	1,736,544
Loans held in portfolio, net of unearned income	1,731,679	1,743,711
Popular U.S. \| Commercial \| Commercial multi-family \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	5,273
Popular U.S. \| Commercial \| Commercial multi-family \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	22,171	0
Popular U.S. \| Commercial \| Commercial multi-family \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	0	1,894
Non-accrual loans	0	1,894
Accruing loans past-due 90 days or more	0	0
Popular U.S. \| Commercial \| CRE non-owner occupied
Financing Receivable, Recorded Investment, Past Due
Past Due	7,575	5,233
Current	2,029,514	1,988,577
Loans held in portfolio, net of unearned income	2,037,089	1,993,810
Popular U.S. \| Commercial \| CRE non-owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	2,569	924
Popular U.S. \| Commercial \| CRE non-owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	4,632	3,640
Popular U.S. \| Commercial \| CRE non-owner occupied \| Past due 90 days or more
Financing Receivable, Recorded Investment, Past Due
Past Due	374	669
Non-accrual loans	374	669
Accruing loans past-due 90 days or more	0	0
Popular U.S. \| Commercial \| CRE owner occupied
Financing Receivable, Recorded Investment, Past Due
Past Due	2,144	1,175
Current	343,430	343,205
Loans held in portfolio, net of unearned income	345,574	344,380

Loans - Loans held-in-portfolio in past due status, non-performing status and accruing loans past-due 90 days or more by loan class (Details) - USD ($)
$ in Thousands