Note Segment reporting (Selected Balance Sheet information) (Detail) - USD ($) $ in Thousands		Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Segment Reporting Information [Line Items]
Total assets		$ 47,535,177	$ 44,277,337	$ 41,242,669
Deposits		39,377,561	35,453,508
PUERTO RICO
Segment Reporting Information [Line Items]
Total assets		36,721,033	33,705,624
Loans		17,036,052	17,591,078
Deposits		30,748,039	27,575,292
UNITED STATES
Segment Reporting Information [Line Items]
Total assets		9,921,233	9,648,865
Loans		6,937,782	6,608,056
Deposits		7,086,447	6,635,153
Other
Segment Reporting Information [Line Items]
Total assets		892,911	922,848
Loans		708,541	743,329
Deposits	[1]	$ 1,543,075	$ 1,243,063

[1] Represents deposits from BPPR operations located in the US and British Virgin Islands.