Note Segment reporting (Selected Balance Sheet information) (Detail) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Segment Reporting Information [Line Items]
Total assets		$ 48,680,607	$ 47,604,577	$ 45,756,761
Deposits		40,879,838	39,710,039
PUERTO RICO
Segment Reporting Information [Line Items]
Total assets		37,656,205	36,863,930
Loans		18,855,650	18,837,742
Deposits		32,343,773	31,237,529
UNITED STATES
Segment Reporting Information [Line Items]
Total assets		10,145,457	9,847,944
Loans		7,158,946	7,034,075
Deposits		7,048,008	6,878,599
Other
Segment Reporting Information [Line Items]
Total assets		878,945	892,703
Loans		677,097	687,494
Deposits	[1]	$ 1,488,057	$ 1,593,911

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