Allowance for credit losses - Allowance Movement (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Financing Receivable, Allowance for Credit Losses
Beginning balance	$ 785,790	$ 918,434	$ 896,250	$ 477,708
Impact of adopting CECL				315,107
Provision for credit losses (benefit)	(58,645)	19,452	(151,924)	271,551
Initial allowance for credit losses - PCD Loans	253	4,823	2,811	5,819
Charge-offs	(31,567)	(38,389)	(109,347)	(196,357)
Recoveries	22,744	21,530	80,785	52,022
Ending balance	718,575	925,850	718,575	925,850
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	9,936	6,717	15,851	8,717
Impact of adopting CECL				(5,460)
Provision for credit losses (benefit)	(1,536)	6,578	(7,451)	10,038
Balance at end of period	8,400	13,295	8,400	13,295
Construction
Financing Receivable, Allowance for Credit Losses
Beginning balance	11,256	6,459	14,237	4,840
Impact of adopting CECL				(2,923)
Provision for credit losses (benefit)	(3,629)	5,837	(1,079)	10,010
Initial allowance for credit losses - PCD Loans	0	0	0	0
Charge-offs	(1)	0	(7,143)	0
Recoveries	2,224	156	3,835	525
Ending balance	9,850	12,452	9,850	12,452
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	5,077	2,816	9,079	419
Impact of adopting CECL				397
Provision for credit losses (benefit)	(203)	3,311	(4,205)	5,311
Balance at end of period	4,874	6,127	4,874	6,127
Mortgages
Financing Receivable, Allowance for Credit Losses
Beginning balance	182,619	222,237	215,716	121,108
Impact of adopting CECL				96,512
Provision for credit losses (benefit)	(14,653)	237	(41,573)	16,930
Initial allowance for credit losses - PCD Loans	253	4,823	2,811	5,819
Charge-offs	(1,159)	(5,229)	(16,588)	(22,968)
Recoveries	3,318	3,270	10,012	7,937
Ending balance	170,378	225,338	170,378	225,338
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	0	0	0	0
Impact of adopting CECL				0
Provision for credit losses (benefit)	0	0	0	0
Balance at end of period	0	0	0	0
Commercial
Financing Receivable, Allowance for Credit Losses
Beginning balance	271,144	316,966	333,380	147,620
Impact of adopting CECL				91,930
Provision for credit losses (benefit)	(32,436)	13,447	(106,380)	91,755
Initial allowance for credit losses - PCD Loans	0	0	0	0
Charge-offs	(9,505)	(2,543)	(15,496)	(9,251)
Recoveries	5,611	4,193	23,310	10,009
Ending balance	234,814	332,063	234,814	332,063
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	4,811	3,840	6,666	830
Impact of adopting CECL				1,611
Provision for credit losses (benefit)	(1,320)	3,262	(3,175)	4,661
Balance at end of period	3,491	7,102	3,491	7,102
Leasing
Financing Receivable, Allowance for Credit Losses
Beginning balance	17,551	13,093	16,863	10,768
Impact of adopting CECL				(713)
Provision for credit losses (benefit)	(5,613)	1,746	(4,414)	11,481
Initial allowance for credit losses - PCD Loans	0	0	0	0
Charge-offs	(1,054)	(957)	(3,247)	(8,681)
Recoveries	750	1,286	2,432	2,313
Ending balance	11,634	15,168	11,634	15,168
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	0	0	0	0
Impact of adopting CECL				0
Provision for credit losses (benefit)	0	0	0	0
Balance at end of period	0	0	0	0
Consumer
Financing Receivable, Allowance for Credit Losses
Beginning balance	303,220	359,679	316,054	193,372
Impact of adopting CECL				130,301
Provision for credit losses (benefit)	(2,314)	(1,815)	1,522	141,375
Initial allowance for credit losses - PCD Loans	0	0	0	0
Charge-offs	(19,848)	(29,660)	(66,873)	(155,457)
Recoveries	10,841	12,625	41,196	31,238
Ending balance	291,899	340,829	291,899	340,829
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	48	61	106	7,468
Impact of adopting CECL				(7,468)
Provision for credit losses (benefit)	(13)	5	(71)	66
Balance at end of period	35	66	35	66
Puerto Rico
Financing Receivable, Allowance for Credit Losses
Beginning balance	661,853	755,782	739,750	432,651
Impact of adopting CECL				270,368
Provision for credit losses (benefit)	(35,992)	7,682	(98,456)	181,109
Initial allowance for credit losses - PCD Loans	253	4,823	2,811	5,819
Charge-offs	(29,904)	(34,041)	(100,457)	(181,214)
Recoveries	20,568	20,272	73,130	45,785
Ending balance	616,778	754,518	616,778	754,518
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	4,657	2,419	9,523	8,439
Impact of adopting CECL				(6,494)
Provision for credit losses (benefit)	(252)	4,667	(5,118)	5,141
Balance at end of period	4,405	7,086	4,405	7,086
Puerto Rico | Construction
Financing Receivable, Allowance for Credit Losses
Beginning balance	1,220	354	4,871	574
Impact of adopting CECL				115
Provision for credit losses (benefit)	(1,532)	4,358	255	3,809
Initial allowance for credit losses - PCD Loans	0	0	0	0
Charge-offs	(1)	0	(6,620)	0
Recoveries	2,224	156	3,405	370
Ending balance	1,911	4,868	1,911	4,868
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	1,405	145	4,610	294
Impact of adopting CECL				(185)
Provision for credit losses (benefit)	663	2,581	(2,542)	2,617
Balance at end of period	2,068	2,726	2,068	2,726
Puerto Rico | Mortgages
Financing Receivable, Allowance for Credit Losses
Beginning balance	166,808	199,250	195,557	116,281
Impact of adopting CECL				86,081
Provision for credit losses (benefit)	(14,110)	1,549	(36,179)	10,533
Initial allowance for credit losses - PCD Loans	253	4,823	2,811	5,819
Charge-offs	(1,157)	(5,217)	(16,585)	(22,940)
Recoveries	3,268	3,253	9,458	7,884
Ending balance	155,062	203,658	155,062	203,658
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	0	0	0	0
Impact of adopting CECL				0
Provision for credit losses (benefit)	0	0	0	0
Balance at end of period	0	0	0	0
Puerto Rico | Commercial
Financing Receivable, Allowance for Credit Losses
Beginning balance	186,784	214,927	225,323	131,063
Impact of adopting CECL				62,393
Provision for credit losses (benefit)	(13,923)	1,562	(63,773)	24,710
Initial allowance for credit losses - PCD Loans	0	0	0	0
Charge-offs	(9,481)	(2,059)	(14,399)	(7,799)
Recoveries	5,124	4,018	21,353	8,081
Ending balance	168,504	218,448	168,504	218,448
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	3,252	2,274	4,913	678
Impact of adopting CECL				1,158
Provision for credit losses (benefit)	(915)	2,086	(2,576)	2,524
Balance at end of period	2,337	4,360	2,337	4,360
Puerto Rico | Leasing
Financing Receivable, Allowance for Credit Losses
Beginning balance	17,551	13,093	16,863	10,768
Impact of adopting CECL				(713)
Provision for credit losses (benefit)	(5,613)	1,746	(4,414)	11,481
Initial allowance for credit losses - PCD Loans	0	0	0	0
Charge-offs	(1,054)	(957)	(3,247)	(8,681)
Recoveries	750	1,286	2,432	2,313
Ending balance	11,634	15,168	11,634	15,168
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	0	0	0	0
Impact of adopting CECL				0
Provision for credit losses (benefit)	0	0	0	0
Balance at end of period	0	0	0	0
Puerto Rico | Consumer
Financing Receivable, Allowance for Credit Losses
Beginning balance	289,490	328,158	297,136	173,965
Impact of adopting CECL				122,492
Provision for credit losses (benefit)	(814)	(1,533)	5,655	130,576
Initial allowance for credit losses - PCD Loans	0	0	0	0
Charge-offs	(18,211)	(25,808)	(59,606)	(141,794)
Recoveries	9,202	11,559	36,482	27,137
Ending balance	279,667	312,376	279,667	312,376
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	0	0	0	7,467
Impact of adopting CECL				(7,467)
Provision for credit losses (benefit)	0	0	0	0
Balance at end of period	0	0	0	0
Popular U.S.
Financing Receivable, Allowance for Credit Losses
Beginning balance	123,937	162,652	156,500	45,057
Impact of adopting CECL				44,739
Provision for credit losses (benefit)	(22,653)	11,770	(53,468)	90,442
Charge-offs	(1,663)	(4,348)	(8,890)	(15,143)
Recoveries	2,176	1,258	7,655	6,237
Ending balance	101,797	171,332	101,797	171,332
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	5,279	4,298	6,328	278
Impact of adopting CECL				1,034
Provision for credit losses (benefit)	(1,284)	1,911	(2,333)	4,897
Balance at end of period	3,995	6,209	3,995	6,209
Popular U.S. | Construction
Financing Receivable, Allowance for Credit Losses
Beginning balance	10,036	6,105	9,366	4,266
Impact of adopting CECL				(3,038)
Provision for credit losses (benefit)	(2,097)	1,479	(1,334)	6,201
Charge-offs	0	0	(523)	0
Recoveries	0	0	430	155
Ending balance	7,939	7,584	7,939	7,584
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	3,672	2,671	4,469	125
Impact of adopting CECL				582
Provision for credit losses (benefit)	(866)	730	(1,663)	2,694
Balance at end of period	2,806	3,401	2,806	3,401
Popular U.S. | Mortgages
Financing Receivable, Allowance for Credit Losses
Beginning balance	15,811	22,987	20,159	4,827
Impact of adopting CECL				10,431
Provision for credit losses (benefit)	(543)	(1,312)	(5,394)	6,397
Charge-offs	(2)	(12)	(3)	(28)
Recoveries	50	17	554	53
Ending balance	15,316	21,680	15,316	21,680
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	0	0	0	0
Impact of adopting CECL				0
Provision for credit losses (benefit)	0	0	0	0
Balance at end of period	0	0	0	0
Popular U.S. | Commercial
Financing Receivable, Allowance for Credit Losses
Beginning balance	84,360	102,039	108,057	16,557
Impact of adopting CECL				29,537
Provision for credit losses (benefit)	(18,513)	11,885	(42,607)	67,045
Charge-offs	(24)	(484)	(1,097)	(1,452)
Recoveries	487	175	1,957	1,928
Ending balance	66,310	113,615	66,310	113,615
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	1,559	1,566	1,753	152
Impact of adopting CECL				453
Provision for credit losses (benefit)	(405)	1,176	(599)	2,137
Balance at end of period	1,154	2,742	1,154	2,742
Popular U.S. | Consumer
Financing Receivable, Allowance for Credit Losses
Beginning balance	13,730	31,521	18,918	19,407
Impact of adopting CECL				7,809
Provision for credit losses (benefit)	(1,500)	(282)	(4,133)	10,799
Charge-offs	(1,637)	(3,852)	(7,267)	(13,663)
Recoveries	1,639	1,066	4,714	4,101
Ending balance	12,232	28,453	12,232	28,453
Off Balance Sheet Credit Loss Liability [Rollforward]
Balance at beginning of period	48	61	106	1
Impact of adopting CECL				(1)
Provision for credit losses (benefit)	(13)	5	(71)	66
Balance at end of period	$ 35	$ 66	$ 35	$ 66