Loans - Amortized cost basis of collateral dependent loans by class (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	$ 580,157	$ 634,621
Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	534,961	608,599
Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	933	4
Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	819	1,438
Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	115	1,545
Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	11,026	10,989
Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	32,303	12,046
Construction | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	14,877	29,057
Construction | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	14,877	29,057
Construction | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Construction | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Construction | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Construction | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Construction | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Mortgages | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	195,145	182,503
Mortgages | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	195,145	182,503
Mortgages | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Mortgages | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Mortgages | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Mortgages | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Mortgages | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | Commercial multi-family | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	1,392	3,056
Commercial | Commercial multi-family | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	1,392	3,056
Commercial | Commercial multi-family | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | Commercial multi-family | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | Commercial multi-family | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | Commercial multi-family | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | Commercial multi-family | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | CRE non-owner occupied | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	250,906	299,223
Commercial | CRE non-owner occupied | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	250,906	299,223
Commercial | CRE non-owner occupied | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | CRE non-owner occupied | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | CRE non-owner occupied | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | CRE non-owner occupied | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | CRE non-owner occupied | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | CRE owner occupied | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	62,291	79,769
Commercial | CRE owner occupied | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	62,291	79,769
Commercial | CRE owner occupied | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | CRE owner occupied | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | CRE owner occupied | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | CRE owner occupied | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | CRE owner occupied | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | Commercial and Industrial | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	47,423	33,595
Commercial | Commercial and Industrial | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	3,160	7,577
Commercial | Commercial and Industrial | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Commercial | Commercial and Industrial | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	819	1,438
Commercial | Commercial and Industrial | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	115	1,545
Commercial | Commercial and Industrial | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	11,026	10,989
Commercial | Commercial and Industrial | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	32,303	12,046
Consumer | Personal loans | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	7,190	7,414
Consumer | Personal loans | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	7,190	7,414
Consumer | Personal loans | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Consumer | Personal loans | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Consumer | Personal loans | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Consumer | Personal loans | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Consumer | Personal loans | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Consumer | Auto Loan | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	767	4
Consumer | Auto Loan | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Consumer | Auto Loan | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	767	4
Consumer | Auto Loan | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Consumer | Auto Loan | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Consumer | Auto Loan | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Consumer | Auto Loan | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Leasing | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	166
Leasing | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0
Leasing | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	166
Leasing | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0
Leasing | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0
Leasing | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0
Leasing | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0
Puerto Rico | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	579,296	622,906
Puerto Rico | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	534,215	598,429
Puerto Rico | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	933	4
Puerto Rico | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	819	1,438
Puerto Rico | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	11,026	10,989
Puerto Rico | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	32,303	12,046
Puerto Rico | Construction | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	14,877	21,497
Puerto Rico | Construction | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	14,877	21,497
Puerto Rico | Construction | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Construction | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Construction | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Construction | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Construction | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Mortgages | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	194,399	181,648
Puerto Rico | Mortgages | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	194,399	181,648
Puerto Rico | Mortgages | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Mortgages | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Mortgages | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Mortgages | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Mortgages | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | Commercial multi-family | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	1,392	1,301
Puerto Rico | Commercial | Commercial multi-family | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	1,392	1,301
Puerto Rico | Commercial | Commercial multi-family | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | Commercial multi-family | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | Commercial multi-family | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | Commercial multi-family | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | Commercial multi-family | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | CRE non-owner occupied | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	250,906	299,223
Puerto Rico | Commercial | CRE non-owner occupied | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	250,906	299,223
Puerto Rico | Commercial | CRE non-owner occupied | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | CRE non-owner occupied | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | CRE non-owner occupied | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | CRE non-owner occupied | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | CRE non-owner occupied | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | CRE owner occupied | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	62,291	79,769
Puerto Rico | Commercial | CRE owner occupied | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	62,291	79,769
Puerto Rico | Commercial | CRE owner occupied | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | CRE owner occupied | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | CRE owner occupied | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | CRE owner occupied | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | CRE owner occupied | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | Commercial and Industrial | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	47,308	32,050
Puerto Rico | Commercial | Commercial and Industrial | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	3,160	7,577
Puerto Rico | Commercial | Commercial and Industrial | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | Commercial and Industrial | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	819	1,438
Puerto Rico | Commercial | Commercial and Industrial | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Commercial | Commercial and Industrial | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	11,026	10,989
Puerto Rico | Commercial | Commercial and Industrial | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	32,303	12,046
Puerto Rico | Consumer | Personal loans | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	7,190	7,414
Puerto Rico | Consumer | Personal loans | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	7,190	7,414
Puerto Rico | Consumer | Personal loans | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Consumer | Personal loans | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Consumer | Personal loans | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Consumer | Personal loans | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Consumer | Personal loans | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Consumer | Auto Loan | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	767	4
Puerto Rico | Consumer | Auto Loan | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Consumer | Auto Loan | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	767	4
Puerto Rico | Consumer | Auto Loan | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Consumer | Auto Loan | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Consumer | Auto Loan | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Consumer | Auto Loan | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Puerto Rico | Leasing | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	166
Puerto Rico | Leasing | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0
Puerto Rico | Leasing | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	166
Puerto Rico | Leasing | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0
Puerto Rico | Leasing | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0
Puerto Rico | Leasing | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0
Puerto Rico | Leasing | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0
Popular U.S. | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	861	11,715
Popular U.S. | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	746	10,170
Popular U.S. | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	115	1,545
Popular U.S. | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Construction | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		7,560
Popular U.S. | Construction | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		7,560
Popular U.S. | Construction | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		0
Popular U.S. | Construction | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		0
Popular U.S. | Construction | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		0
Popular U.S. | Construction | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		0
Popular U.S. | Construction | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		0
Popular U.S. | Mortgages | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	746	855
Popular U.S. | Mortgages | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	746	855
Popular U.S. | Mortgages | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Mortgages | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Mortgages | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Mortgages | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Mortgages | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Commercial | Commercial multi-family | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		1,755
Popular U.S. | Commercial | Commercial multi-family | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		1,755
Popular U.S. | Commercial | Commercial multi-family | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		0
Popular U.S. | Commercial | Commercial multi-family | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		0
Popular U.S. | Commercial | Commercial multi-family | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		0
Popular U.S. | Commercial | Commercial multi-family | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		0
Popular U.S. | Commercial | Commercial multi-family | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross		0
Popular U.S. | Commercial | Commercial and Industrial | Collateral assets
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	115	1,545
Popular U.S. | Commercial | Commercial and Industrial | Real Estate
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Commercial | Commercial and Industrial | Auto
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Commercial | Commercial and Industrial | Equipment
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Commercial | Commercial and Industrial | Taxi medallions
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	115	1,545
Popular U.S. | Commercial | Commercial and Industrial | Accounts receivable
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	0	0
Popular U.S. | Commercial | Commercial and Industrial | Other
Accounts, Notes, Loans and Financing Receivable
Notes Receivable Gross	$ 0	$ 0