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	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Recorded Investment, Past Due
Past Due	$ 2,003,170	$ 2,269,553
Current	27,128,458	27,115,643
Loans held in portfolio, net of unearned income	29,131,628	29,385,196
Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	335,230	361,661
Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	137,042	142,054
Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	1,530,898	1,765,838
Non-accrual loans	698,142	737,774
Accruing loans past-due 90 days or more	832,756	1,028,064
Construction
Financing Receivable, Recorded Investment, Past Due
Past Due	34,149	50,369
Current	873,587	875,839
Loans held in portfolio, net of unearned income	907,736	926,208
Construction \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	11,749	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	22,400	29,057
Non-accrual loans	22,400	29,057
Accruing loans past-due 90 days or more	0	0
Mortgages
Financing Receivable, Recorded Investment, Past Due
Past Due	1,501,222	1,775,902
Current	6,307,630	6,114,778
Loans held in portfolio, net of unearned income	7,808,852	7,890,680
Mortgages \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	188,962	229,024
Mortgages \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	85,532	103,190
Mortgages \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	1,226,728	1,443,688
Non-accrual loans	405,574	429,207
Accruing loans past-due 90 days or more	821,154	1,014,481
Commercial \| Commercial multi-family
Financing Receivable, Recorded Investment, Past Due
Past Due	31,195	8,468
Current	1,861,899	1,887,523
Loans held in portfolio, net of unearned income	1,893,094	1,895,991
Commercial \| Commercial multi-family \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	30,381	6,069
Commercial \| Commercial multi-family \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	0
Commercial \| Commercial multi-family \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	814	2,399
Non-accrual loans	814	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	111,541	88,062
Current	3,992,512	3,913,081
Loans held in portfolio, net of unearned income	4,104,053	4,001,143
Commercial \| CRE non-owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	9,219	3,113
Commercial \| CRE non-owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	25,406	7,143
Commercial \| CRE non-owner occupied \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	76,916	77,806
Non-accrual loans	76,916	77,806
Accruing loans past-due 90 days or more	0	0
Commercial \| CRE owner occupied
Financing Receivable, Recorded Investment, Past Due
Past Due	105,019	102,664
Current	1,736,897	1,840,611
Loans held in portfolio, net of unearned income	1,841,916	1,943,275
Commercial \| CRE owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	12,186	8,461
Commercial \| CRE owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	2,758	1,868
Commercial \| CRE owner occupied \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	90,075	92,335
Non-accrual loans	90,075	92,335
Accruing loans past-due 90 days or more	0	0
Commercial \| Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Past Due	48,601	50,290
Current	5,554,822	5,723,611
Loans held in portfolio, net of unearned income	5,603,423	5,773,901
Commercial \| Commercial and Industrial \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	11,096	11,340
Commercial \| Commercial and Industrial \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	1,971	847
Commercial \| Commercial and Industrial \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	35,534	38,103
Non-accrual loans	34,965	37,540
Accruing loans past-due 90 days or more	569	563
Leasing
Financing Receivable, Recorded Investment, Past Due
Past Due	12,012	14,009
Current	1,232,944	1,183,652
Loans held in portfolio, net of unearned income	1,244,956	1,197,661
Leasing \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	7,564	9,141
Leasing \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	1,408	1,427
Leasing \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	3,040	3,441
Non-accrual loans	3,040	3,441
Accruing loans past-due 90 days or more	0	0
Consumer \| Credit cards
Financing Receivable, Recorded Investment, Past Due
Past Due	19,486	23,970
Current	858,277	895,996
Loans held in portfolio, net of unearned income	877,763	919,966
Consumer \| Credit cards \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	4,824	6,550
Consumer \| Credit cards \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	3,883	4,619
Consumer \| Credit cards \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	10,779	12,801
Non-accrual loans	0	0
Accruing loans past-due 90 days or more	10,779	12,801
Consumer \| Home equity lines of credit
Financing Receivable, Recorded Investment, Past Due
Past Due	7,032	8,301
Current	86,129	90,449
Loans held in portfolio, net of unearned income	93,161	98,750
Consumer \| Home equity lines of credit \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	121	420
Consumer \| Home equity lines of credit \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	10	342
Consumer \| Home equity lines of credit \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	6,901	7,539
Non-accrual loans	6,855	7,491
Accruing loans past-due 90 days or more	46	48
Consumer \| Personal loans
Financing Receivable, Recorded Investment, Past Due
Past Due	45,105	50,041
Current	1,381,634	1,426,944
Loans held in portfolio, net of unearned income	1,426,739	1,476,985
Consumer \| Personal loans \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	11,372	12,741
Consumer \| Personal loans \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,916	9,439
Consumer \| Personal loans \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	26,817	27,861
Non-accrual loans	26,817	27,861
Accruing loans past-due 90 days or more	0	0
Consumer \| Auto Loan
Financing Receivable, Recorded Investment, Past Due
Past Due	71,584	81,618
Current	3,131,553	3,050,610
Loans held in portfolio, net of unearned income	3,203,137	3,132,228
Consumer \| Auto Loan \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	47,396	53,186
Consumer \| Auto Loan \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	8,783	12,696
Consumer \| Auto Loan \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	15,405	15,736
Non-accrual loans	15,405	15,736
Accruing loans past-due 90 days or more	0	0
Consumer \| Other
Financing Receivable, Recorded Investment, Past Due
Past Due	16,224	15,859
Current	110,574	112,549
Loans held in portfolio, net of unearned income	126,798	128,408
Consumer \| Other \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	360	304
Consumer \| Other \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	375	483
Consumer \| Other \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	15,489	15,072
Non-accrual loans	15,281	14,901
Accruing loans past-due 90 days or more	208	171
Puerto Rico
Financing Receivable, Recorded Investment, Past Due
Past Due	1,890,047	2,146,682
Current	19,444,218	19,426,598
Loans held in portfolio, net of unearned income	21,334,265	21,573,280
Puerto Rico \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	258,683	297,700
Puerto Rico \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	132,639	120,544
Puerto Rico \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	1,498,725	1,728,438
Non-accrual loans	665,978	700,377
Accruing loans past-due 90 days or more	832,747	1,028,061
Puerto Rico \| Construction
Financing Receivable, Recorded Investment, Past Due
Past Due	15,516	21,497
Current	145,081	135,609
Loans held in portfolio, net of unearned income	160,597	157,106
Puerto Rico \| Construction \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	639	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	1,471,635	1,712,152
Current	5,204,344	5,057,991
Loans held in portfolio, net of unearned income	6,675,979	6,770,143
Puerto Rico \| Mortgages \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	175,930	195,602
Puerto Rico \| Mortgages \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	83,770	87,726
Puerto Rico \| Mortgages \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	1,211,935	1,428,824
Non-accrual loans	390,781	414,343
Accruing loans past-due 90 days or more	821,154	1,014,481
Puerto Rico \| Commercial \| Commercial multi-family
Financing Receivable, Recorded Investment, Past Due
Past Due	1,010	1,301
Current	137,097	150,979
Loans held in portfolio, net of unearned income	138,107	152,280
Puerto Rico \| Commercial \| Commercial multi-family \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	196	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	814	505
Non-accrual loans	814	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	102,869	82,829
Current	1,958,129	1,924,504
Loans held in portfolio, net of unearned income	2,060,998	2,007,333
Puerto Rico \| Commercial \| CRE non-owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	939	2,189
Puerto Rico \| Commercial \| CRE non-owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	25,406	3,503
Puerto Rico \| Commercial \| CRE non-owner occupied \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	76,524	77,137
Non-accrual loans	76,524	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	98,615	101,489
Current	1,413,356	1,497,406
Loans held in portfolio, net of unearned income	1,511,971	1,598,895
Puerto Rico \| Commercial \| CRE owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,749	8,270
Puerto Rico \| Commercial \| CRE owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	2,114	1,218
Puerto Rico \| Commercial \| CRE owner occupied \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	89,752	92,001
Non-accrual loans	89,752	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	38,853	46,010
Current	4,032,359	4,183,098
Loans held in portfolio, net of unearned income	4,071,212	4,229,108
Puerto Rico \| Commercial \| Commercial and Industrial \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	3,870	10,223
Puerto Rico \| Commercial \| Commercial and Industrial \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	650	775
Puerto Rico \| Commercial \| Commercial and Industrial \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	34,333	35,012
Non-accrual loans	33,773	34,449
Accruing loans past-due 90 days or more	560	563
Puerto Rico \| Leasing
Financing Receivable, Recorded Investment, Past Due
Past Due	12,012	14,009
Current	1,232,944	1,183,652
Loans held in portfolio, net of unearned income	1,244,956	1,197,661
Puerto Rico \| Leasing \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	7,564	9,141
Puerto Rico \| Leasing \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	1,408	1,427
Puerto Rico \| Leasing \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	3,040	3,441
Non-accrual loans	3,040	3,441
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Consumer \| Credit cards
Financing Receivable, Recorded Investment, Past Due
Past Due	19,486	23,967
Current	858,255	895,968
Loans held in portfolio, net of unearned income	877,741	919,935
Puerto Rico \| Consumer \| Credit cards \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	4,824	6,550
Puerto Rico \| Consumer \| Credit cards \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	3,883	4,619
Puerto Rico \| Consumer \| Credit cards \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	10,779	12,798
Non-accrual loans	0	0
Accruing loans past-due 90 days or more	10,779	12,798
Puerto Rico \| Consumer \| Home equity lines of credit
Financing Receivable, Recorded Investment, Past Due
Past Due	46	232
Current	3,498	3,947
Loans held in portfolio, net of unearned income	3,544	4,179
Puerto Rico \| Consumer \| Home equity lines of credit \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	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	46	48
Non-accrual loans	0	0
Accruing loans past-due 90 days or more	46	48
Puerto Rico \| Consumer \| Personal loans
Financing Receivable, Recorded Investment, Past Due
Past Due	42,197	45,739
Current	1,219,094	1,232,008
Loans held in portfolio, net of unearned income	1,261,291	1,277,747
Puerto Rico \| Consumer \| Personal loans \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	10,216	11,255
Puerto Rico \| Consumer \| Personal loans \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,250	8,097
Puerto Rico \| Consumer \| Personal loans \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	25,731	26,387
Non-accrual loans	25,731	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	71,584	81,618
Current	3,131,553	3,050,610
Loans held in portfolio, net of unearned income	3,203,137	3,132,228
Puerto Rico \| Consumer \| Auto Loan \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	47,396	53,186
Puerto Rico \| Consumer \| Auto Loan \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	8,783	12,696
Puerto Rico \| Consumer \| Auto Loan \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	15,405	15,736
Non-accrual loans	15,405	15,736
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Consumer \| Other
Financing Receivable, Recorded Investment, Past Due
Past Due	16,224	15,839
Current	108,508	110,826
Loans held in portfolio, net of unearned income	124,732	126,665
Puerto Rico \| Consumer \| Other \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	360	304
Puerto Rico \| Consumer \| Other \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	375	483
Puerto Rico \| Consumer \| Other \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	15,489	15,052
Non-accrual loans	15,281	14,881
Accruing loans past-due 90 days or more	208	171
Popular U.S.
Financing Receivable, Recorded Investment, Past Due
Past Due	113,123	122,871
Current	7,684,240	7,689,045
Loans held in portfolio, net of unearned income	7,797,363	7,811,916
Popular U.S. \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	76,547	63,961
Popular U.S. \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	4,403	21,510
Popular U.S. \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	32,173	37,400
Non-accrual loans	32,164	37,397
Accruing loans past-due 90 days or more	9	3
Popular U.S. \| Construction
Financing Receivable, Recorded Investment, Past Due
Past Due	18,633	28,872
Current	728,506	740,230
Loans held in portfolio, net of unearned income	747,139	769,102
Popular U.S. \| Construction \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	11,110	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	7,523	7,560
Non-accrual loans	7,523	7,560
Accruing loans past-due 90 days or more	0	0
Popular U.S. \| Mortgages
Financing Receivable, Recorded Investment, Past Due
Past Due	29,587	63,750
Current	1,103,286	1,056,787
Loans held in portfolio, net of unearned income	1,132,873	1,120,537
Popular U.S. \| Mortgages \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	13,032	33,422
Popular U.S. \| Mortgages \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	1,762	15,464
Popular U.S. \| Mortgages \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	14,793	14,864
Non-accrual loans	14,793	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	30,185	7,167
Current	1,724,802	1,736,544
Loans held in portfolio, net of unearned income	1,754,987	1,743,711
Popular U.S. \| Commercial \| Commercial multi-family \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	30,185	5,273
Popular U.S. \| Commercial \| Commercial multi-family \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	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	8,672	5,233
Current	2,034,383	1,988,577
Loans held in portfolio, net of unearned income	2,043,055	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	8,280	924
Popular U.S. \| Commercial \| CRE non-owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	3,640
Popular U.S. \| Commercial \| CRE non-owner occupied \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	392	669
Non-accrual loans	392	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	6,404	1,175
Current	323,541	343,205
Loans held in portfolio, net of unearned income	329,945	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