Note Income taxes (Components of deferred tax assets and liabilities) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Deferred tax assets:
Tax credits available for carryforward	$ 18,027	$ 18,510
Net operating loss and other carryforward available	1,223,823	1,238,222
Postretirement and pension benefits	83,925	94,741
Allowance for loan losses	655,096	649,107
Accelerated depreciation	11,605	9,828
Difference between the assigned values and the tax basis of assets and liabilities recognized in purchase business combinations	17,107	13,160
Other temporary differences	36,262	31,127
Total gross deferred tax assets	2,055,324	2,068,697
Deferred tax liabilities:
FDIC-assisted transaction	58,009	58,363
Indefinite-lived intangibles	79,497	73,974
Unrealized net gain on trading and available-for-sale securities	23,590	21,335
Other temporary differences	10,014	8,477
Total gross deferred tax liabilities	171,110	162,149
Valuation allowance	678,086	664,287
Net deferred tax asset	1,206,128	1,242,261
PUERTO RICO
Deferred tax assets:
Tax credits available for carryforward	16,069	16,552
Net operating loss and other carryforward available	117,273	112,929
Postretirement and pension benefits	83,925	94,741
Allowance for loan losses	616,572	628,127
Accelerated depreciation	1,325	605
Difference between the assigned values and the tax basis of assets and liabilities recognized in purchase business combinations	17,107	13,160
Other temporary differences	22,750	16,417
Total gross deferred tax assets	878,758	889,362
Deferred tax liabilities:
FDIC-assisted transaction	58,009	58,363
Indefinite-lived intangibles	31,083	28,412
Unrealized net gain on trading and available-for-sale securities	31,127	30,334
Other temporary differences	9,429	7,892
Total gross deferred tax liabilities	129,648	125,001
Valuation allowance	62,213	46,951
Net deferred tax asset	686,897	717,410
UNITED STATES
Deferred tax assets:
Tax credits available for carryforward	1,958	1,958
Net operating loss and other carryforward available	1,106,550	1,125,293
Postretirement and pension benefits	0	0
Allowance for loan losses	38,524	20,980
Accelerated depreciation	10,280	9,223
Difference between the assigned values and the tax basis of assets and liabilities recognized in purchase business combinations	0	0
Other temporary differences	13,512	14,710
Total gross deferred tax assets	1,176,566	1,179,335
Deferred tax liabilities:
FDIC-assisted transaction	0	0
Indefinite-lived intangibles	48,414	45,562
Unrealized net gain on trading and available-for-sale securities	(7,537)	(8,999)
Other temporary differences	585	585
Total gross deferred tax liabilities	41,462	37,148
Valuation allowance	615,873	617,336
Net deferred tax asset	519,231	524,851
Deferred loans origination fees
Deferred tax assets:
Deferred income	5,248	6,622
Deferred loans origination fees | PUERTO RICO
Deferred tax assets:
Deferred income	3,768	4,335
Deferred loans origination fees | UNITED STATES
Deferred tax assets:
Deferred income	1,480	2,287
Deferred gain
Deferred tax assets:
Deferred income	4,262	4,884
Deferred gain | PUERTO RICO
Deferred tax assets:
Deferred income	0	0
Deferred gain | UNITED STATES
Deferred tax assets:
Deferred income	4,262	4,884
Intercompany deferred gains
Deferred tax assets:
Deferred income	(31)	2,496
Intercompany deferred gains | PUERTO RICO
Deferred tax assets:
Deferred income	(31)	2,496
Intercompany deferred gains | UNITED STATES
Deferred tax assets:
Deferred income	$ 0	$ 0