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, 2020	Dec. 31, 2019	Sep. 30, 2019
Financing Receivable, Recorded Investment, Past Due
Past Due	$ 2,511,974	$ 1,803,602
Current	26,880,536	25,603,271
Loans held-in-portfolio	29,392,510	27,406,873	$ 27,007,975
Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	456,154	454,281
Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	108,505	208,221
Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	1,947,315	1,141,100
Non-accrual loans	734,368	527,841
Accruing loans past-due 90 days or more	1,212,947	460,133
Construction
Financing Receivable, Recorded Investment, Past Due
Past Due	35,478	1,700
Current	900,796	829,392
Loans held-in-portfolio	936,274	831,092	754,056
Construction \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	4,895	1,555
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	30,583	145
Non-accrual loans	30,583	145
Accruing loans past-due 90 days or more	0	0
Mortgages
Financing Receivable, Recorded Investment, Past Due
Past Due	1,987,098	1,299,443
Current	5,937,343	5,884,089
Loans held-in-portfolio	7,924,441	7,183,532	7,168,619
Mortgages \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	339,291	300,480
Mortgages \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	65,819	150,221
Mortgages \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	1,581,988	848,742
Non-accrual loans	384,544	294,799
Accruing loans past-due 90 days or more	1,197,444	439,662
Legacy
Financing Receivable, Recorded Investment, Past Due
Past Due	1,417	2,056
Current	14,751	20,049
Loans held-in-portfolio	16,168	22,105	23,192
Legacy \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	41	49
Legacy \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	16	8
Legacy \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	1,360	1,999
Non-accrual loans	1,360	1,999
Accruing loans past-due 90 days or more	0	0
Commercial
Financing Receivable, Recorded Investment, Past Due
Loans held-in-portfolio		12,312,751	12,208,449
Commercial \| Commercial multi-family
Financing Receivable, Recorded Investment, Past Due
Past Due	6,764	6,688
Current	1,874,151	1,788,471
Loans held-in-portfolio	1,880,915	1,795,159
Commercial \| Commercial multi-family \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	3,480	2,950
Commercial \| Commercial multi-family \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	129	129
Commercial \| Commercial multi-family \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	3,155	3,609
Non-accrual loans	3,155	3,570
Accruing loans past-due 90 days or more	0	0
Commercial \| CRE non-owner occupied
Financing Receivable, Recorded Investment, Past Due
Past Due	120,744	60,675
Current	3,889,411	3,917,839
Loans held-in-portfolio	4,010,155	3,978,514
Commercial \| CRE non-owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	19,523	11,486
Commercial \| CRE non-owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	2,014	5,244
Commercial \| CRE non-owner occupied \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	99,207	43,945
Non-accrual loans	99,207	40,249
Accruing loans past-due 90 days or more	0	0
Commercial \| CRE owner occupied
Financing Receivable, Recorded Investment, Past Due
Past Due	112,858	96,220
Current	1,818,543	1,829,244
Loans held-in-portfolio	1,931,401	1,925,464
Commercial \| CRE owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	10,840	7,454
Commercial \| CRE owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	4,223	3,978
Commercial \| CRE owner occupied \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	97,795	84,788
Non-accrual loans	97,795	69,527
Accruing loans past-due 90 days or more	0	0
Commercial \| Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Past Due	62,701	68,109
Current	5,726,202	4,545,505
Loans held-in-portfolio	5,788,903	4,613,614
Commercial \| Commercial and Industrial \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	7,361	9,234
Commercial \| Commercial and Industrial \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,426	1,774
Commercial \| Commercial and Industrial \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	48,914	57,101
Non-accrual loans	48,221	37,414
Accruing loans past-due 90 days or more	693	544
Leasing
Financing Receivable, Recorded Investment, Past Due
Past Due	13,921	18,724
Current	1,139,187	1,040,783
Loans held-in-portfolio	1,153,108	1,059,507	1,022,484
Leasing \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	8,254	12,014
Leasing \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	2,450	3,053
Leasing \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	3,217	3,657
Non-accrual loans	3,217	3,657
Accruing loans past-due 90 days or more	0	0
Consumer
Financing Receivable, Recorded Investment, Past Due
Loans held-in-portfolio		5,997,886	5,831,175
Consumer \| Credit cards
Financing Receivable, Recorded Investment, Past Due
Past Due	26,941	38,747
Current	904,629	1,085,089
Loans held-in-portfolio	931,570	1,123,836
Consumer \| Credit cards \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,125	11,358
Consumer \| Credit cards \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,308	7,928
Consumer \| Credit cards \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	14,508	19,461
Non-accrual loans	0	0
Accruing loans past-due 90 days or more	14,508	19,461
Consumer \| Home equity lines of credit
Financing Receivable, Recorded Investment, Past Due
Past Due	9,433	10,710
Current	99,790	111,671
Loans held-in-portfolio	109,223	122,381
Consumer \| Home equity lines of credit \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	1,438	404
Consumer \| Home equity lines of credit \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	351	352
Consumer \| Home equity lines of credit \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	7,644	9,954
Non-accrual loans	7,586	9,954
Accruing loans past-due 90 days or more	58	0
Consumer \| Personal loans
Financing Receivable, Recorded Investment, Past Due
Past Due	55,086	49,063
Current	1,484,461	1,643,527
Loans held-in-portfolio	1,539,547	1,692,590
Consumer \| Personal loans \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	14,807	15,767
Consumer \| Personal loans \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	9,166	10,934
Consumer \| Personal loans \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	31,113	22,362
Non-accrual loans	31,113	21,595
Accruing loans past-due 90 days or more	0	61
Consumer \| Auto Loan
Financing Receivable, Recorded Investment, Past Due
Past Due	63,718	135,499
Current	2,981,735	2,782,023
Loans held-in-portfolio	3,045,453	2,917,522
Consumer \| Auto Loan \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	39,887	81,169
Consumer \| Auto Loan \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	10,377	23,182
Consumer \| Auto Loan \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	13,454	31,148
Non-accrual loans	13,454	31,148
Accruing loans past-due 90 days or more	0	0
Consumer \| Other
Financing Receivable, Recorded Investment, Past Due
Past Due	15,815	15,968
Current	109,537	125,589
Loans held-in-portfolio	125,352	141,557
Consumer \| Other \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	212	361
Consumer \| Other \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	1,226	1,418
Consumer \| Other \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	14,377	14,189
Non-accrual loans	14,133	13,784
Accruing loans past-due 90 days or more	244	405
Puerto Rico
Financing Receivable, Recorded Investment, Past Due
Past Due	2,456,194	1,728,407
Current	19,208,449	18,451,825
Loans held-in-portfolio	21,664,643	20,180,232	19,932,582
Puerto Rico \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	449,521	432,805
Puerto Rico \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	100,053	202,212
Puerto Rico \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	1,906,620	1,093,390
Non-accrual loans	693,676	499,200
Accruing loans past-due 90 days or more	1,212,944	460,133
Puerto Rico \| Construction
Financing Receivable, Recorded Investment, Past Due
Past Due	26,409	1,674
Current	169,656	135,796
Loans held-in-portfolio	196,065	137,470	124,072
Puerto Rico \| Construction \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	4,895	1,555
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	21,514	119
Non-accrual loans	21,514	119
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Mortgages
Financing Receivable, Recorded Investment, Past Due
Past Due	1,963,714	1,268,854
Current	4,863,266	4,897,894
Loans held-in-portfolio	6,826,980	6,166,748	6,235,576
Puerto Rico \| Mortgages \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	336,824	285,006
Puerto Rico \| Mortgages \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	59,386	146,197
Puerto Rico \| Mortgages \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	1,567,504	837,651
Non-accrual loans	370,060	283,708
Accruing loans past-due 90 days or more	1,197,444	439,662
Puerto Rico \| Commercial
Financing Receivable, Recorded Investment, Past Due
Loans held-in-portfolio		7,261,130	7,168,653
Puerto Rico \| Commercial \| Commercial multi-family
Financing Receivable, Recorded Investment, Past Due
Past Due	5,009	4,582
Current	139,169	143,267
Loans held-in-portfolio	144,178	147,849
Puerto Rico \| Commercial \| Commercial multi-family \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	3,480	2,941
Puerto Rico \| Commercial \| Commercial multi-family \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	129	129
Puerto Rico \| Commercial \| Commercial multi-family \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	1,400	1,512
Non-accrual loans	1,400	1,473
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	120,348	59,347
Current	1,950,794	2,048,871
Loans held-in-portfolio	2,071,142	2,108,218
Puerto Rico \| Commercial \| CRE non-owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	19,523	10,439
Puerto Rico \| Commercial \| CRE non-owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	2,014	5,244
Puerto Rico \| Commercial \| CRE non-owner occupied \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	98,811	43,664
Non-accrual loans	98,811	39,968
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Commercial \| CRE owner occupied
Financing Receivable, Recorded Investment, Past Due
Past Due	111,863	94,219
Current	1,458,412	1,492,110
Loans held-in-portfolio	1,570,275	1,586,329
Puerto Rico \| Commercial \| CRE owner occupied \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	10,187	5,704
Puerto Rico \| Commercial \| CRE owner occupied \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	4,223	3,978
Puerto Rico \| Commercial \| CRE owner occupied \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	97,453	84,537
Non-accrual loans	97,453	69,276
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Commercial \| Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Past Due	58,198	47,582
Current	4,233,554	3,371,152
Loans held-in-portfolio	4,291,752	3,418,734
Puerto Rico \| Commercial \| Commercial and Industrial \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,809	8,780
Puerto Rico \| Commercial \| Commercial and Industrial \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,376	1,646
Puerto Rico \| Commercial \| Commercial and Industrial \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	45,013	37,156
Non-accrual loans	44,320	36,538
Accruing loans past-due 90 days or more	693	544
Puerto Rico \| Leasing
Financing Receivable, Recorded Investment, Past Due
Past Due	13,921	18,724
Current	1,139,187	1,040,783
Loans held-in-portfolio	1,153,108	1,059,507	1,022,484
Puerto Rico \| Leasing \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	8,254	12,014
Puerto Rico \| Leasing \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	2,450	3,053
Puerto Rico \| Leasing \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	3,217	3,657
Non-accrual loans	3,217	3,657
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Consumer
Financing Receivable, Recorded Investment, Past Due
Loans held-in-portfolio		5,555,377	5,381,797
Puerto Rico \| Consumer \| Credit cards
Financing Receivable, Recorded Investment, Past Due
Past Due	26,935	38,747
Current	904,604	1,085,053
Loans held-in-portfolio	931,539	1,123,800
Puerto Rico \| Consumer \| Credit cards \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,125	11,358
Puerto Rico \| Consumer \| Credit cards \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,305	7,928
Puerto Rico \| Consumer \| Credit cards \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	14,505	19,461
Non-accrual loans	0	0
Accruing loans past-due 90 days or more	14,505	19,461
Puerto Rico \| Consumer \| Home equity lines of credit
Financing Receivable, Recorded Investment, Past Due
Past Due	239	85
Current	4,075	4,953
Loans held-in-portfolio	4,314	5,038
Puerto Rico \| Consumer \| Home equity lines of credit \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	181	0
Puerto Rico \| Consumer \| Home equity lines of credit \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	85
Puerto Rico \| Consumer \| Home equity lines of credit \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	58	0
Non-accrual loans	0	0
Accruing loans past-due 90 days or more	58	0
Puerto Rico \| Consumer \| Personal loans
Financing Receivable, Recorded Investment, Past Due
Past Due	50,078	43,129
Current	1,255,707	1,325,021
Loans held-in-portfolio	1,305,785	1,368,150
Puerto Rico \| Consumer \| Personal loans \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	13,166	13,481
Puerto Rico \| Consumer \| Personal loans \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	7,569	9,352
Puerto Rico \| Consumer \| Personal loans \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	29,343	20,296
Non-accrual loans	29,343	19,529
Accruing loans past-due 90 days or more	0	61
Puerto Rico \| Consumer \| Auto Loan
Financing Receivable, Recorded Investment, Past Due
Past Due	63,718	135,499
Current	2,981,735	2,782,023
Loans held-in-portfolio	3,045,453	2,917,522
Puerto Rico \| Consumer \| Auto Loan \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	39,887	81,169
Puerto Rico \| Consumer \| Auto Loan \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	10,377	23,182
Puerto Rico \| Consumer \| Auto Loan \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	13,454	31,148
Non-accrual loans	13,454	31,148
Accruing loans past-due 90 days or more	0	0
Puerto Rico \| Consumer \| Other
Financing Receivable, Recorded Investment, Past Due
Past Due	15,762	15,965
Current	108,290	124,902
Loans held-in-portfolio	124,052	140,867
Puerto Rico \| Consumer \| Other \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	190	358
Puerto Rico \| Consumer \| Other \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	1,224	1,418
Puerto Rico \| Consumer \| Other \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	14,348	14,189
Non-accrual loans	14,104	13,784
Accruing loans past-due 90 days or more	244	405
Popular U.S.
Financing Receivable, Recorded Investment, Past Due
Past Due	55,780	75,195
Current	7,672,087	7,151,446
Loans held-in-portfolio	7,727,867	7,226,641	7,075,393
Popular U.S. \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,633	21,476
Popular U.S. \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	8,452	6,009
Popular U.S. \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	40,695	47,710
Non-accrual loans	40,692	28,641
Accruing loans past-due 90 days or more	3	0
Popular U.S. \| Construction
Financing Receivable, Recorded Investment, Past Due
Past Due	9,069	26
Current	731,140	693,596
Loans held-in-portfolio	740,209	693,622	629,984
Popular U.S. \| Construction \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	0	0
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	9,069	26
Non-accrual loans	9,069	26
Accruing loans past-due 90 days or more	0	0
Popular U.S. \| Mortgages
Financing Receivable, Recorded Investment, Past Due
Past Due	23,384	30,589
Current	1,074,077	986,195
Loans held-in-portfolio	1,097,461	1,016,784	933,043
Popular U.S. \| Mortgages \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	2,467	15,474
Popular U.S. \| Mortgages \| Past Due 60 To 89 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	6,433	4,024
Popular U.S. \| Mortgages \| Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Past Due	14,484	11,091
Non-accrual loans	14,484	11,091
Accruing loans past-due 90 days or more	0	0
Popular U.S. \| Legacy
Financing Receivable, Recorded Investment, Past Due
Past Due	1,417	2,056
Current	14,751	20,049
Loans held-in-portfolio	16,168	22,105	23,192
Popular U.S. \| Legacy \| Past Due 30 To 59 Days
Financing Receivable, Recorded Investment, Past Due
Past Due	41	49
Popular U.S. \| Legacy \| Past Due 60 To 89 Days

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