Note Allowance for loan losses (Quantitative information by loan class for loans modified as T D R) (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($) loans	Jun. 30, 2015 USD ($) loans	Jun. 30, 2016 USD ($) loans	Jun. 30, 2015 USD ($) loans
Troubled Debt Restructuring
Loan count | loans	917	829	1,780	1,690
Pre-Modification Recorded Investment	$ 36,044	$ 77,361	$ 81,474	$ 131,313
Post Modification Recorded Investment	35,398	82,428	80,178	138,970
Increase (decrease) in the allowance for loan losses as a result of modification	$ 3,433	$ 13,970	$ 11,522	$ 20,298
Commercial multi-family
Troubled Debt Restructuring
Loan count | loans	0	0	0	2
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 551
Post Modification Recorded Investment	0	0	0	551
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 2
CRE non-owner occupied
Troubled Debt Restructuring
Loan count | loans	1	10	3	13
Pre-Modification Recorded Investment	$ 197	$ 48,719	$ 6,520	$ 66,719
Post Modification Recorded Investment	197	48,868	6,504	66,866
Increase (decrease) in the allowance for loan losses as a result of modification	$ 7	$ 10,682	$ 4,169	$ 13,668
CRE owner occupied
Troubled Debt Restructuring
Loan count | loans	17	14	34	19
Pre-Modification Recorded Investment	$ 7,755	$ 5,031	$ 10,850	$ 9,790
Post Modification Recorded Investment	6,625	4,484	9,774	9,036
Increase (decrease) in the allowance for loan losses as a result of modification	$ 201	$ 162	$ 337	$ 333
Commercial and industrial
Troubled Debt Restructuring
Loan count | loans	9	12	15	22
Pre-Modification Recorded Investment	$ 1,057	$ 6,834	$ 3,586	$ 12,367
Post Modification Recorded Investment	1,056	6,997	3,583	12,886
Increase (decrease) in the allowance for loan losses as a result of modification	$ (25)	$ 439	$ (20)	$ 662
Construction
Troubled Debt Restructuring
Loan count | loans	0	0	0	1
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 268
Post Modification Recorded Investment	0	0	0	259
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ (166)
Mortgages
Troubled Debt Restructuring
Loan count | loans	196	135	404	289
Pre-Modification Recorded Investment	$ 18,764	$ 8,471	$ 44,336	$ 24,841
Post Modification Recorded Investment	18,547	13,339	43,021	31,569
Increase (decrease) in the allowance for loan losses as a result of modification	$ 1,398	$ 1,054	$ 3,627	$ 2,475
Legacy
Troubled Debt Restructuring
Loan count | loans	0	0	0	0
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post Modification Recorded Investment	0	0	0	0
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 0
Leasing
Troubled Debt Restructuring
Loan count | loans	0	3	0	16
Pre-Modification Recorded Investment	$ 0	$ 99	$ 0	$ 422
Post Modification Recorded Investment	0	99	0	424
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 23	$ 0	$ 97
Credit cards
Troubled Debt Restructuring
Loan count | loans	409	358	758	773
Pre-Modification Recorded Investment	$ 3,775	$ 3,265	$ 7,031	$ 6,882
Post Modification Recorded Investment	4,388	3,687	8,053	7,753
Increase (decrease) in the allowance for loan losses as a result of modification	$ 651	$ 568	$ 1,227	$ 1,197
Home equity lines of credit
Troubled Debt Restructuring
Loan count | loans	2	2	3	3
Pre-Modification Recorded Investment	$ 208	$ 74	$ 355	$ 74
Post Modification Recorded Investment	251	75	398	167
Increase (decrease) in the allowance for loan losses as a result of modification	$ 139	$ 16	$ 216	$ 25
Personal
Troubled Debt Restructuring
Loan count | loans	265	280	531	522
Pre-Modification Recorded Investment	$ 4,195	$ 4,781	$ 8,608	$ 9,283
Post Modification Recorded Investment	4,237	4,779	8,648	9,279
Increase (decrease) in the allowance for loan losses as a result of modification	$ 1,044	$ 1,012	$ 1,931	$ 1,979
Auto
Troubled Debt Restructuring
Loan count | loans	7	4	11	8
Pre-Modification Recorded Investment	$ 61	$ 60	$ 133	$ 60
Post Modification Recorded Investment	64	62	140	113
Increase (decrease) in the allowance for loan losses as a result of modification	$ 13	$ 9	$ 25	$ 17
Other
Troubled Debt Restructuring
Loan count | loans	11	11	21	22
Pre-Modification Recorded Investment	$ 32	$ 27	$ 55	$ 56
Post Modification Recorded Investment	33	38	57	67
Increase (decrease) in the allowance for loan losses as a result of modification	$ 5	$ 5	$ 10	$ 9
PUERTO RICO
Troubled Debt Restructuring
Loan count | loans	908	823	1,758	1,674
Pre-Modification Recorded Investment	$ 35,042	$ 77,070	$ 79,158	$ 130,554
Post Modification Recorded Investment	34,314	82,130	77,717	137,116
Increase (decrease) in the allowance for loan losses as a result of modification	$ 3,084	$ 13,854	$ 10,673	$ 20,091
PUERTO RICO | Commercial multi-family
Troubled Debt Restructuring
Loan count | loans	0	0	0	2
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 551
Post Modification Recorded Investment	0	0	0	551
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 2
PUERTO RICO | CRE non-owner occupied
Troubled Debt Restructuring
Loan count | loans	1	10	3	13
Pre-Modification Recorded Investment	$ 197	$ 48,719	$ 6,520	$ 66,719
Post Modification Recorded Investment	197	48,868	6,504	66,866
Increase (decrease) in the allowance for loan losses as a result of modification	$ 7	$ 10,682	$ 4,169	$ 13,668
PUERTO RICO | CRE owner occupied
Troubled Debt Restructuring
Loan count | loans	17	14	34	19
Pre-Modification Recorded Investment	$ 7,755	$ 5,031	$ 10,850	$ 9,790
Post Modification Recorded Investment	6,625	4,484	9,774	9,036
Increase (decrease) in the allowance for loan losses as a result of modification	$ 201	$ 162	$ 337	$ 333
PUERTO RICO | Commercial and industrial
Troubled Debt Restructuring
Loan count | loans	9	12	15	22
Pre-Modification Recorded Investment	$ 1,057	$ 6,834	$ 3,586	$ 12,367
Post Modification Recorded Investment	1,056	6,997	3,583	12,886
Increase (decrease) in the allowance for loan losses as a result of modification	$ (25)	$ 439	$ (20)	$ 662
PUERTO RICO | Construction
Troubled Debt Restructuring
Loan count | loans	0	0	0	1
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 268
Post Modification Recorded Investment	0	0	0	259
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ (166)
PUERTO RICO | Mortgages
Troubled Debt Restructuring
Loan count | loans	189	133	385	278
Pre-Modification Recorded Investment	$ 17,970	$ 8,284	$ 42,375	$ 24,186
Post Modification Recorded Investment	17,714	13,146	40,958	29,912
Increase (decrease) in the allowance for loan losses as a result of modification	$ 1,188	$ 957	$ 2,994	$ 2,296
PUERTO RICO | Leasing
Troubled Debt Restructuring
Loan count | loans	0	3	0	16
Pre-Modification Recorded Investment	$ 0	$ 99	$ 0	$ 422
Post Modification Recorded Investment	0	99	0	424
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 23	$ 0	$ 97
PUERTO RICO | Credit cards
Troubled Debt Restructuring
Loan count | loans	409	358	758	773
Pre-Modification Recorded Investment	$ 3,775	$ 3,265	$ 7,031	$ 6,882
Post Modification Recorded Investment	4,388	3,687	8,053	7,753
Increase (decrease) in the allowance for loan losses as a result of modification	$ 651	$ 568	$ 1,227	$ 1,197
PUERTO RICO | Home equity lines of credit
Troubled Debt Restructuring
Loan count | loans	0	0	0	0
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post Modification Recorded Investment	0	0	0	0
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 0
PUERTO RICO | Personal
Troubled Debt Restructuring
Loan count | loans	265	278	531	520
Pre-Modification Recorded Investment	$ 4,195	$ 4,751	$ 8,608	$ 9,253
Post Modification Recorded Investment	4,237	4,749	8,648	9,249
Increase (decrease) in the allowance for loan losses as a result of modification	$ 1,044	$ 1,009	$ 1,931	$ 1,976
PUERTO RICO | Auto
Troubled Debt Restructuring
Loan count | loans	7	4	11	8
Pre-Modification Recorded Investment	$ 61	$ 60	$ 133	$ 60
Post Modification Recorded Investment	64	62	140	113
Increase (decrease) in the allowance for loan losses as a result of modification	$ 13	$ 9	$ 25	$ 17
PUERTO RICO | Other
Troubled Debt Restructuring
Loan count | loans	11	11	21	22
Pre-Modification Recorded Investment	$ 32	$ 27	$ 55	$ 56
Post Modification Recorded Investment	33	38	57	67
Increase (decrease) in the allowance for loan losses as a result of modification	$ 5	$ 5	$ 10	$ 9
UNITED STATES
Troubled Debt Restructuring
Loan count | loans	9	6	22	16
Pre-Modification Recorded Investment	$ 1,002	$ 291	$ 2,316	$ 759
Post Modification Recorded Investment	1,084	298	2,461	1,854
Increase (decrease) in the allowance for loan losses as a result of modification	$ 349	$ 116	$ 849	$ 207
UNITED STATES | Commercial multi-family
Troubled Debt Restructuring
Loan count | loans	0	0	0	0
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post Modification Recorded Investment	0	0	0	0
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 0
UNITED STATES | CRE non-owner occupied
Troubled Debt Restructuring
Loan count | loans	0	0	0	0
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post Modification Recorded Investment	0	0	0	0
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 0
UNITED STATES | CRE owner occupied
Troubled Debt Restructuring
Loan count | loans	0	0	0	0
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post Modification Recorded Investment	0	0	0	0
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 0
UNITED STATES | Commercial and industrial
Troubled Debt Restructuring
Loan count | loans	0	0	0	0
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post Modification Recorded Investment	0	0	0	0
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 0
UNITED STATES | Construction
Troubled Debt Restructuring
Loan count | loans	0	0	0	0
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post Modification Recorded Investment	0	0	0	0
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 0
UNITED STATES | Mortgages
Troubled Debt Restructuring
Loan count | loans	7	2	19	11
Pre-Modification Recorded Investment	$ 794	$ 187	$ 1,961	$ 655
Post Modification Recorded Investment	833	193	2,063	1,657
Increase (decrease) in the allowance for loan losses as a result of modification	$ 210	$ 97	$ 633	$ 179
UNITED STATES | Legacy
Troubled Debt Restructuring
Loan count | loans	0	0	0	0
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post Modification Recorded Investment	0	0	0	0
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 0
UNITED STATES | Credit cards
Troubled Debt Restructuring
Loan count | loans	0	0	0	0
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post Modification Recorded Investment	0	0	0	0
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 0
UNITED STATES | Home equity lines of credit
Troubled Debt Restructuring
Loan count | loans	2	2	3	3
Pre-Modification Recorded Investment	$ 208	$ 74	$ 355	$ 74
Post Modification Recorded Investment	251	75	398	167
Increase (decrease) in the allowance for loan losses as a result of modification	$ 139	$ 16	$ 216	$ 25
UNITED STATES | Personal
Troubled Debt Restructuring
Loan count | loans	0	2	0	2
Pre-Modification Recorded Investment	$ 0	$ 30	$ 0	$ 30
Post Modification Recorded Investment	0	30	0	30
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 3	$ 0	$ 3
UNITED STATES | Auto
Troubled Debt Restructuring
Loan count | loans	0	0	0	0
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post Modification Recorded Investment	0	0	0	0
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 0
UNITED STATES | Other
Troubled Debt Restructuring
Loan count | loans	0	0	0	0
Pre-Modification Recorded Investment	$ 0	$ 0	$ 0	$ 0
Post Modification Recorded Investment	0	0	0	0
Increase (decrease) in the allowance for loan losses as a result of modification	$ 0	$ 0	$ 0	$ 0