Note Income taxes (Components of deferred tax assets and liabilities) (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Deferred tax assets:
Tax credits available for carryforward	$ 24,359	$ 24,048
Net operating loss and other carryforward available	849,015	823,670
Postretirement and pension benefits	81,525	85,488
Allowance for loan losses	591,258	624,170
Accelerated depreciation	8,376	8,383
FDIC-assisted transaction	105,249
Difference in outside basis from pass-through entities	25,495	30,424
Other temporary differences	35,900	31,985
Total gross deferred tax assets	1,727,376	1,635,689
Deferred tax liabilities:
FDIC-assisted transaction		60,402
Indefinite-lived intangibles	73,998	64,982
Unrealized net gain (loss) on trading and available-for-sale securities	(7,006)	18,403
Other temporary differences	12,147	10,262
Total gross deferred tax liabilities	79,139	154,049
Valuation allowance	505,444	447,824
Net deferred tax asset	1,142,793	1,033,816
PUERTO RICO
Deferred tax assets:
Tax credits available for carryforward	16,500	16,069
Net operating loss and other carryforward available	114,193	115,512
Postretirement and pension benefits	81,525	85,488
Allowance for loan losses	569,336	603,462
Accelerated depreciation	1,300	1,300
FDIC-assisted transaction	105,249
Difference in outside basis from pass-through entities	25,495	30,424
Other temporary differences	28,387	25,084
Total gross deferred tax assets	946,527	881,232
Deferred tax liabilities:
FDIC-assisted transaction		60,402
Indefinite-lived intangibles	34,579	31,973
Unrealized net gain (loss) on trading and available-for-sale securities	11,609	26,364
Other temporary differences	11,302	9,876
Total gross deferred tax liabilities	57,490	128,615
Valuation allowance	84,282	67,263
Net deferred tax asset	804,755	685,354
UNITED STATES
Deferred tax assets:
Tax credits available for carryforward	7,859	7,979
Net operating loss and other carryforward available	734,822	708,158
Postretirement and pension benefits	0	0
Allowance for loan losses	21,922	20,708
Accelerated depreciation	7,076	7,083
FDIC-assisted transaction	0
Difference in outside basis from pass-through entities	0	0
Other temporary differences	7,513	6,901
Total gross deferred tax assets	780,849	754,457
Deferred tax liabilities:
FDIC-assisted transaction		0
Indefinite-lived intangibles	39,419	33,009
Unrealized net gain (loss) on trading and available-for-sale securities	(18,615)	(7,961)
Other temporary differences	845	386
Total gross deferred tax liabilities	21,649	25,434
Valuation allowance	421,162	380,561
Net deferred tax asset	338,038	348,462
Deferred loans origination fees
Deferred tax assets:
Deferred income	2,262	4,627
Deferred loans origination fees | PUERTO RICO
Deferred tax assets:
Deferred income	3,258	3,669
Deferred loans origination fees | UNITED STATES
Deferred tax assets:
Deferred income	(996)	958
Deferred gain
Deferred tax assets:
Deferred income	2,653	2,670
Deferred gain | PUERTO RICO
Deferred tax assets:
Deferred income	0	0
Deferred gain | UNITED STATES
Deferred tax assets:
Deferred income	2,653	2,670
Intercompany deferred gains
Deferred tax assets:
Deferred income	1,284	224
Intercompany deferred gains | PUERTO RICO
Deferred tax assets:
Deferred income	1,284	224
Intercompany deferred gains | UNITED STATES
Deferred tax assets:
Deferred income	$ 0	$ 0