Note Commitments and Contingencies (Schedule of Direct Exposure to Puerto Rico Government by Maturity) (Detail) - PR Government Direct Exposure - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	$ 656,165	$ 669,337
From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	68,413
From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	1,455
From Public Corporation - Puerto Rico Aqueduct And Sewer Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	27,650
From Public Corporation - Puerto Rico Electric Power Authority [Member]
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	40,936
From Public Corporation - Puerto Rico Highways And Transportation Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	4
From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	504,389	501,901
Total concentration of risk	517,707
Outstanding Balance
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	564,867	577,759
Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	17,619
Outstanding Balance | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	1,455
Outstanding Balance | From Public Corporation - Puerto Rico Aqueduct And Sewer Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	464
Outstanding Balance | From Public Corporation - Puerto Rico Electric Power Authority [Member]
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	40,936
Outstanding Balance | From Public Corporation - Puerto Rico Highways And Transportation Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	4
Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	504,389
Loans Member | Outstanding Balance
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	490,363	502,251
Loans Member | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
Loans Member | Outstanding Balance | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
Loans Member | Outstanding Balance | From Public Corporation - Puerto Rico Aqueduct And Sewer Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
Loans Member | Outstanding Balance | From Public Corporation - Puerto Rico Electric Power Authority [Member]
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	40,914
Loans Member | Outstanding Balance | From Public Corporation - Puerto Rico Highways And Transportation Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
Loans Member | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	449,449
Securities Investment Member | Outstanding Balance
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	74,504	$ 75,508
Securities Investment Member | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	17,619
Securities Investment Member | Outstanding Balance | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	1,455
Securities Investment Member | Outstanding Balance | From Public Corporation - Puerto Rico Aqueduct And Sewer Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	464
Securities Investment Member | Outstanding Balance | From Public Corporation - Puerto Rico Electric Power Authority [Member]
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	22
Securities Investment Member | Outstanding Balance | From Public Corporation - Puerto Rico Highways And Transportation Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	4
Securities Investment Member | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	54,940
Within 1 year | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	50,794
Within 1 year | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	3
Within 1 year | From Public Corporation - Puerto Rico Aqueduct And Sewer Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	27,186
Within 1 year | From Public Corporation - Puerto Rico Electric Power Authority [Member]
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	40,914
Within 1 year | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	73,324
Within 1 year | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
Within 1 year | Outstanding Balance | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	3
Within 1 year | Outstanding Balance | From Public Corporation - Puerto Rico Aqueduct And Sewer Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
Within 1 year | Outstanding Balance | From Public Corporation - Puerto Rico Electric Power Authority [Member]
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	40,914
Within 1 year | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	60,006
Within 1 year | Loans Member | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
Within 1 year | Loans Member | Outstanding Balance | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
Within 1 year | Loans Member | Outstanding Balance | From Public Corporation - Puerto Rico Aqueduct And Sewer Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
Within 1 year | Loans Member | Outstanding Balance | From Public Corporation - Puerto Rico Electric Power Authority [Member]
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	40,914
Within 1 year | Loans Member | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	56,956
Within 1 year | Securities Investment Member | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
Within 1 year | Securities Investment Member | Outstanding Balance | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	3
Within 1 year | Securities Investment Member | Outstanding Balance | From Public Corporation - Puerto Rico Aqueduct And Sewer Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
Within 1 year | Securities Investment Member | Outstanding Balance | From Public Corporation - Puerto Rico Electric Power Authority [Member]
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
Within 1 year | Securities Investment Member | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	3,050
After 1 and within 5 years | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	887
After 1 and within 5 years | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	1,092
After 1 and within 5 years | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	145,205
After 1 and within 5 years | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	887
After 1 and within 5 years | Outstanding Balance | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	1,092
After 1 and within 5 years | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	145,205
After 1 and within 5 years | Loans Member | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
After 1 and within 5 years | Loans Member | Outstanding Balance | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
After 1 and within 5 years | Loans Member | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	130,935
After 1 and within 5 years | Securities Investment Member | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	887
After 1 and within 5 years | Securities Investment Member | Outstanding Balance | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	1,092
After 1 and within 5 years | Securities Investment Member | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	14,270
After 5 to 10 years | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	3,044
After 5 to 10 years | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	360
After 5 to 10 years | From Public Corporation - Puerto Rico Highways And Transportation Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	4
After 5 to 10 years | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	157,117
After 5 to 10 years | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	3,044
After 5 to 10 years | Outstanding Balance | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	360
After 5 to 10 years | Outstanding Balance | From Public Corporation - Puerto Rico Highways And Transportation Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	4
After 5 to 10 years | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	157,117
After 5 to 10 years | Loans Member | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
After 5 to 10 years | Loans Member | Outstanding Balance | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
After 5 to 10 years | Loans Member | Outstanding Balance | From Public Corporation - Puerto Rico Highways And Transportation Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
After 5 to 10 years | Loans Member | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	138,187
After 5 to 10 years | Securities Investment Member | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	3,044
After 5 to 10 years | Securities Investment Member | Outstanding Balance | From Government Development Bank
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	360
After 5 to 10 years | Securities Investment Member | Outstanding Balance | From Public Corporation - Puerto Rico Highways And Transportation Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	4
After 5 to 10 years | Securities Investment Member | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	18,930
After 10 years | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	13,688
After 10 years | From Public Corporation - Puerto Rico Aqueduct And Sewer Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	464
After 10 years | From Public Corporation - Puerto Rico Electric Power Authority [Member]
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	22
After 10 years | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Total concentration of risk	142,061
After 10 years | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	13,688
After 10 years | Outstanding Balance | From Public Corporation - Puerto Rico Aqueduct And Sewer Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	464
After 10 years | Outstanding Balance | From Public Corporation - Puerto Rico Electric Power Authority [Member]
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	22
After 10 years | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	142,061
After 10 years | Loans Member | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
After 10 years | Loans Member | Outstanding Balance | From Public Corporation - Puerto Rico Aqueduct And Sewer Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
After 10 years | Loans Member | Outstanding Balance | From Public Corporation - Puerto Rico Electric Power Authority [Member]
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	0
After 10 years | Loans Member | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	123,371
After 10 years | Securities Investment Member | Outstanding Balance | From PR Central Government
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	13,688
After 10 years | Securities Investment Member | Outstanding Balance | From Public Corporation - Puerto Rico Aqueduct And Sewer Authority
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	464
After 10 years | Securities Investment Member | Outstanding Balance | From Public Corporation - Puerto Rico Electric Power Authority [Member]
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	22
After 10 years | Securities Investment Member | Outstanding Balance | From Municipalities
Direct Exposure To The Puerto Rico Government By Maturity [Line Items]
Outstanding concentration of risk	$ 18,690