Allowance for credit losses - Allowance Movement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	$ 477,708	$ 569,348
Impact of adopting CECL	(315,107)
Provision (reversal of provision)	(188,995)	(41,825)
Allowance on purchased financial assets with credit deterioration	429
Charge-offs	(78,683)	(79,841)
Recoveries	16,160	19,296
Balance at end of period	919,716	550,628
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL	119,343	101,958	$ 79,926
General ALLL		448,670
Impaired loans		1,034,037
Ending balance: loans collectively evaluated for impairment		25,613,671
Loans held-in-portfolio	27,662,272	26,647,708	27,406,873
Construction
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	4,778	7,424
Impact of adopting CECL	2,871
Provision (reversal of provision)	(510)	(47)
Allowance on purchased financial assets with credit deterioration	0
Charge-offs	0	(22)
Recoveries	174	47
Balance at end of period	2,591	7,496
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL	0	19	6
General ALLL		7,477
Impaired loans		13,848
Ending balance: loans collectively evaluated for impairment		777,472
Loans held-in-portfolio	902,380	791,320	831,092
Mortgages
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	121,108	147,412
Impact of adopting CECL	(96,512)
Provision (reversal of provision)	(14,575)	(6,298)
Allowance on purchased financial assets with credit deterioration	429
Charge-offs	(8,315)	(13,425)
Recoveries	2,778	2,013
Balance at end of period	227,087	142,298
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL	72,215	43,139	42,012
General ALLL		99,159
Impaired loans		524,803
Ending balance: loans collectively evaluated for impairment		6,682,377
Loans held-in-portfolio	7,094,757	7,207,180	7,183,532
Legacy
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	630	969
Impact of adopting CECL	(382)
Provision (reversal of provision)	(913)	855
Allowance on purchased financial assets with credit deterioration	0
Charge-offs	(9)	164
Recoveries	110	551
Balance at end of period	2,026	829
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		0
General ALLL		829
Impaired loans		0
Ending balance: loans collectively evaluated for impairment		24,404
Loans held-in-portfolio	20,435	24,404	22,105
Commercial
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	147,052	239,115
Impact of adopting CECL	(91,496)
Provision (reversal of provision)	(67,180)	(4,802)
Allowance on purchased financial assets with credit deterioration	0
Charge-offs	(3,562)	(22,942)
Recoveries	2,882	3,514
Balance at end of period	305,048	224,489
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL	20,089	33,476	16,443
General ALLL		191,013
Impaired loans		383,494
Ending balance: loans collectively evaluated for impairment		11,674,816
Loans held-in-portfolio		12,058,310	12,312,751
Leasing
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	10,768	11,486
Impact of adopting CECL	713
Provision (reversal of provision)	(5,841)	891
Allowance on purchased financial assets with credit deterioration	0
Charge-offs	(3,775)	(2,096)
Recoveries	468	610
Balance at end of period	12,589	9,109
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL	23	321	61
General ALLL		8,788
Impaired loans		1,018
Ending balance: loans collectively evaluated for impairment		962,214
Loans held-in-portfolio	1,088,542	963,232	1,059,507
Consumer
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	193,372	162,942
Impact of adopting CECL	(130,301)
Provision (reversal of provision)	(99,976)	(32,424)
Allowance on purchased financial assets with credit deterioration	0
Charge-offs	(63,022)	(41,520)
Recoveries	9,748	12,561
Balance at end of period	370,375	166,407
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL	27,016	25,003	21,404
General ALLL		141,404
Impaired loans		110,874
Ending balance: loans collectively evaluated for impairment		5,492,388
Loans held-in-portfolio		5,603,262	5,997,886
Puerto Rico
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	432,651	507,158
Impact of adopting CECL	(270,368)
Provision (reversal of provision)	(113,004)	(31,454)
Allowance on purchased financial assets with credit deterioration	429
Charge-offs	(73,159)	(70,622)
Recoveries	13,642	16,393
Balance at end of period	756,935	484,383
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		97,722
General ALLL		386,661
Impaired loans		1,001,861
Ending balance: loans collectively evaluated for impairment		18,994,489
Loans held-in-portfolio	20,223,881	19,996,350	20,180,232
Puerto Rico | Construction
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	574	886
Impact of adopting CECL	(115)
Provision (reversal of provision)	289	81
Allowance on purchased financial assets with credit deterioration	0
Charge-offs	0	(22)
Recoveries	19	39
Balance at end of period	419	822
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		19
General ALLL		803
Impaired loans		1,788
Ending balance: loans collectively evaluated for impairment		89,584
Loans held-in-portfolio	164,390	91,372	137,470
Puerto Rico | Mortgages
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	116,281	142,978
Impact of adopting CECL	(86,081)
Provision (reversal of provision)	(5,547)	(6,061)
Allowance on purchased financial assets with credit deterioration	429
Charge-offs	(8,306)	(13,174)
Recoveries	2,768	1,991
Balance at end of period	202,800	137,856
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		40,779
General ALLL		97,077
Impaired loans		515,365
Ending balance: loans collectively evaluated for impairment		5,860,223
Loans held-in-portfolio	6,016,008	6,375,588	6,166,748
Puerto Rico | Commercial
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	131,063	207,214
Impact of adopting CECL	(62,393)
Provision (reversal of provision)	(14,974)	1,689
Allowance on purchased financial assets with credit deterioration	0
Charge-offs	(2,994)	(19,461)
Recoveries	2,414	2,867
Balance at end of period	207,850	188,931
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		33,253
General ALLL		155,678
Impaired loans		381,803
Ending balance: loans collectively evaluated for impairment		7,009,319
Loans held-in-portfolio		7,391,122	7,261,130
Puerto Rico | Leasing
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	10,768	11,486
Impact of adopting CECL	713
Provision (reversal of provision)	(5,841)	891
Allowance on purchased financial assets with credit deterioration	0
Charge-offs	(3,775)	(2,096)
Recoveries	468	610
Balance at end of period	12,589	9,109
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		321
General ALLL		8,788
Impaired loans		1,018
Ending balance: loans collectively evaluated for impairment		962,214
Loans held-in-portfolio	1,088,542	963,232	1,059,507
Puerto Rico | Consumer
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	173,965	144,594
Impact of adopting CECL	(122,492)
Provision (reversal of provision)	(86,931)	(28,054)
Allowance on purchased financial assets with credit deterioration	0
Charge-offs	(58,084)	(35,869)
Recoveries	7,973	10,886
Balance at end of period	333,277	147,665
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		23,350
General ALLL		124,315
Impaired loans		101,887
Ending balance: loans collectively evaluated for impairment		5,073,149
Loans held-in-portfolio		5,175,036	5,555,377
Popular U.S.
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	45,057	62,190
Impact of adopting CECL	(44,739)
Provision (reversal of provision)	(75,991)	(10,371)
Charge-offs	(5,524)	(9,219)
Recoveries	2,518	2,903
Balance at end of period	162,781	66,245
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		4,236
General ALLL		62,009
Impaired loans		32,176
Ending balance: loans collectively evaluated for impairment		6,619,182
Loans held-in-portfolio	7,438,391	6,651,358	7,226,641
Popular U.S. | Construction
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	4,204	6,538
Impact of adopting CECL	2,986
Provision (reversal of provision)	(799)	(128)
Charge-offs	0	0
Recoveries	155	8
Balance at end of period	2,172	6,674
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		0
General ALLL		6,674
Impaired loans		12,060
Ending balance: loans collectively evaluated for impairment		687,888
Loans held-in-portfolio	737,990	699,948	693,622
Popular U.S. | Mortgages
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	4,827	4,434
Impact of adopting CECL	(10,431)
Provision (reversal of provision)	(9,028)	(237)
Charge-offs	(9)	(251)
Recoveries	10	22
Balance at end of period	24,287	4,442
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		2,360
General ALLL		2,082
Impaired loans		9,438
Ending balance: loans collectively evaluated for impairment		822,154
Loans held-in-portfolio	1,078,749	831,592	1,016,784
Popular U.S. | Legacy
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	630	969
Impact of adopting CECL	(382)
Provision (reversal of provision)	(913)	855
Charge-offs	(9)	164
Recoveries	110	551
Balance at end of period	2,026	829
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		0
General ALLL		829
Impaired loans		0
Ending balance: loans collectively evaluated for impairment		24,404
Loans held-in-portfolio	20,435	24,404	22,105
Popular U.S. | Commercial
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	15,989	31,901
Impact of adopting CECL	(29,103)
Provision (reversal of provision)	(52,206)	(6,491)
Charge-offs	(568)	(3,481)
Recoveries	468	647
Balance at end of period	97,198	35,558
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		223
General ALLL		35,335
Impaired loans		1,691
Ending balance: loans collectively evaluated for impairment		4,665,497
Loans held-in-portfolio		4,667,188	5,051,621
Popular U.S. | Consumer
Financing Receivable, Allowance for Credit Losses
Balance at beginning of period	19,407	18,348
Impact of adopting CECL	(7,809)
Provision (reversal of provision)	(13,045)	(4,370)
Charge-offs	(4,938)	(5,651)
Recoveries	1,775	1,675
Balance at end of period	$ 37,098	18,742
Financing Receivable Allowance For Credit Loss Additional Information Abstract
Specific ALLL		1,653
General ALLL		17,089
Impaired loans		8,987
Ending balance: loans collectively evaluated for impairment		419,239
Loans held-in-portfolio		$ 428,226	$ 442,509