Loans - Amortized cost basis and interest income recognized on non-accrual loans (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)
Financing receivable nonaccrual status
Non-accrual with no allowance	$ 250,806
Non-accrual with allowance	517,869
Interest income recognized	3,267
Construction
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	0
Interest income recognized	0
Mortgages
Financing receivable nonaccrual status
Non-accrual with no allowance	138,066
Non-accrual with allowance	278,575
Interest income recognized	1,152
Legacy
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	1,980
Interest income recognized	0
Commercial | Commercial multi-family
Financing receivable nonaccrual status
Non-accrual with no allowance	2,097
Non-accrual with allowance	1,379
Interest income recognized	1
Commercial | CRE non-owner occupied
Financing receivable nonaccrual status
Non-accrual with no allowance	41,150
Non-accrual with allowance	68,173
Interest income recognized	193
Commercial | CRE owner occupied
Financing receivable nonaccrual status
Non-accrual with no allowance	31,003
Non-accrual with allowance	71,129
Interest income recognized	519
Commercial | Commercial and Industrial
Financing receivable nonaccrual status
Non-accrual with no allowance	29,353
Non-accrual with allowance	14,224
Interest income recognized	209
Leasing
Financing receivable nonaccrual status
Non-accrual with no allowance	242
Non-accrual with allowance	3,834
Interest income recognized	(35)
Consumer | Home equity lines of credit
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	9,322
Interest income recognized	8
Consumer | Personal loans
Financing receivable nonaccrual status
Non-accrual with no allowance	7,346
Non-accrual with allowance	30,828
Interest income recognized	685
Consumer | Auto Loan
Financing receivable nonaccrual status
Non-accrual with no allowance	1,549
Non-accrual with allowance	24,882
Interest income recognized	407
Consumer | Other
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	13,543
Interest income recognized	128
Puerto Rico
Financing receivable nonaccrual status
Non-accrual with no allowance	244,278
Non-accrual with allowance	491,405
Interest income recognized	3,061
Puerto Rico | Construction
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	0
Interest income recognized	0
Puerto Rico | Mortgages
Financing receivable nonaccrual status
Non-accrual with no allowance	138,066
Non-accrual with allowance	266,399
Interest income recognized	1,115
Puerto Rico | Legacy
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	0
Interest income recognized	0
Puerto Rico | Commercial | Commercial multi-family
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	1,379
Interest income recognized	1
Puerto Rico | Commercial | CRE non-owner occupied
Financing receivable nonaccrual status
Non-accrual with no allowance	41,150
Non-accrual with allowance	67,904
Interest income recognized	193
Puerto Rico | Commercial | CRE owner occupied
Financing receivable nonaccrual status
Non-accrual with no allowance	31,003
Non-accrual with allowance	70,884
Interest income recognized	519
Puerto Rico | Commercial | Commercial and Industrial
Financing receivable nonaccrual status
Non-accrual with no allowance	24,922
Non-accrual with allowance	13,862
Interest income recognized	209
Puerto Rico | Leasing
Financing receivable nonaccrual status
Non-accrual with no allowance	242
Non-accrual with allowance	3,834
Interest income recognized	(35)
Puerto Rico | Consumer | Home equity lines of credit
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	0
Interest income recognized	0
Puerto Rico | Consumer | Personal loans
Financing receivable nonaccrual status
Non-accrual with no allowance	7,346
Non-accrual with allowance	28,718
Interest income recognized	524
Puerto Rico | Consumer | Auto Loan
Financing receivable nonaccrual status
Non-accrual with no allowance	1,549
Non-accrual with allowance	24,882
Interest income recognized	407
Puerto Rico | Consumer | Other
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	13,543
Interest income recognized	128
Popular U.S.
Financing receivable nonaccrual status
Non-accrual with no allowance	6,528
Non-accrual with allowance	26,464
Interest income recognized	206
Popular U.S. | Construction
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	0
Interest income recognized	0
Popular U.S. | Mortgages
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	12,176
Interest income recognized	37
Popular U.S. | Legacy
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	1,980
Interest income recognized	0
Popular U.S. | Commercial | Commercial multi-family
Financing receivable nonaccrual status
Non-accrual with no allowance	2,097
Non-accrual with allowance	0
Interest income recognized	0
Popular U.S. | Commercial | CRE non-owner occupied
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	269
Interest income recognized	0
Popular U.S. | Commercial | CRE owner occupied
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	245
Interest income recognized	0
Popular U.S. | Commercial | Commercial and Industrial
Financing receivable nonaccrual status
Non-accrual with no allowance	4,431
Non-accrual with allowance	362
Interest income recognized	0
Popular U.S. | Leasing
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	0
Interest income recognized	0
Popular U.S. | Consumer | Home equity lines of credit
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	9,322
Interest income recognized	8
Popular U.S. | Consumer | Personal loans
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	2,110
Interest income recognized	161
Popular U.S. | Consumer | Auto Loan
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	0
Interest income recognized	0
Popular U.S. | Consumer | Other
Financing receivable nonaccrual status
Non-accrual with no allowance	0
Non-accrual with allowance	0
Interest income recognized	$ 0