Note Income taxes (Components of deferred tax assets and liabilities) (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Tax credits available for carryforward	$ 23,928	$ 24,048
Net operating loss and other carryforward available	826,624	823,670
Postretirement and pension benefits	84,204	85,488
Allowance for loan losses	617,264	624,170
Accelerated depreciation	8,513	8,383
Difference in outside basis from pass-through entities	27,034	30,424
Other temporary differences	33,971	31,985
Total gross deferred tax assets	1,629,261	1,635,689
Deferred tax liabilities:
FDIC-assisted transaction	60,406	60,402
Indefinite-lived intangibles	66,983	64,982
Unrealized net gain (loss) on trading and available-for-sale securities	5,506	18,403
Other temporary differences	10,585	10,262
Total gross deferred tax liabilities	143,480	154,049
Valuation allowance	455,940	447,824
Net deferred tax asset	1,029,841	1,033,816
PUERTO RICO
Deferred tax assets:
Tax credits available for carryforward	16,069	16,069
Net operating loss and other carryforward available	120,973	115,512
Postretirement and pension benefits	84,204	85,488
Allowance for loan losses	596,211	603,462
Accelerated depreciation	1,300	1,300
Difference in outside basis from pass-through entities	27,034	30,424
Other temporary differences	27,293	25,084
Total gross deferred tax assets	877,618	881,232
Deferred tax liabilities:
FDIC-assisted transaction	60,406	60,402
Indefinite-lived intangibles	32,848	31,973
Unrealized net gain (loss) on trading and available-for-sale securities	19,457	26,364
Other temporary differences	10,199	9,876
Total gross deferred tax liabilities	122,910	128,615
Valuation allowance	74,489	67,263
Net deferred tax asset	680,219	685,354
UNITED STATES
Deferred tax assets:
Tax credits available for carryforward	7,859	7,979
Net operating loss and other carryforward available	705,651	708,158
Postretirement and pension benefits	0	0
Allowance for loan losses	21,053	20,708
Accelerated depreciation	7,213	7,083
Difference in outside basis from pass-through entities	0	0
Other temporary differences	6,678	6,901
Total gross deferred tax assets	751,643	754,457
Deferred tax liabilities:
FDIC-assisted transaction	0	0
Indefinite-lived intangibles	34,135	33,009
Unrealized net gain (loss) on trading and available-for-sale securities	(13,951)	(7,961)
Other temporary differences	386	386
Total gross deferred tax liabilities	20,570	25,434
Valuation allowance	381,451	380,561
Net deferred tax asset	349,622	348,462
Deferred loans origination fees
Deferred tax assets:
Deferred income	3,803	4,627
Deferred loans origination fees | PUERTO RICO
Deferred tax assets:
Deferred income	3,210	3,669
Deferred loans origination fees | UNITED STATES
Deferred tax assets:
Deferred income	593	958
Deferred gain
Deferred tax assets:
Deferred income	2,596	2,670
Deferred gain | PUERTO RICO
Deferred tax assets:
Deferred income	0	0
Deferred gain | UNITED STATES
Deferred tax assets:
Deferred income	2,596	2,670
Intercompany deferred gains
Deferred tax assets:
Deferred income	1,324	224
Intercompany deferred gains | PUERTO RICO
Deferred tax assets:
Deferred income	1,324	224
Intercompany deferred gains | UNITED STATES
Deferred tax assets:
Deferred income	$ 0	$ 0