Note Segment reporting (Results of Operations) (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018		Jun. 30, 2017	Jun. 30, 2018		Jun. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net Interest income (expense)	$ 414,136		$ 374,479	$ 807,183		$ 736,577
Provision (reversal) for loan losses	60,054		52,479	131,117		93,177
Non interest Income	234,809		116,793	348,306		232,662
Amortization of intangibles	2,324		2,344	4,649		4,689
Depreciation expense	12,742		12,129	25,575		23,928
Other operating expenses	322,602		292,362	629,446		589,536
Income tax (benefit) expense	(28,560)		35,732	(6,405)		68,738
Net income (loss)	279,783		96,226	371,107		189,171
Segment assets	47,535,177		41,242,669	47,535,177		41,242,669	$ 44,277,337
Reportable Segment
Segment Reporting Information [Line Items]
Net Interest income (expense)	428,196		389,319	835,461		766,486
Provision (reversal) for loan losses	60,074		58,164	131,158		98,862
Non interest Income	225,189		107,198	326,016		211,717
Amortization of intangibles	2,324		2,344	4,649		4,689
Depreciation expense	12,569		11,972	25,215		23,608
Other operating expenses	300,590		273,858	586,203		551,734
Income tax (benefit) expense	(19,949)		41,658	6,987		82,876
Net income (loss)	297,777		108,521	407,265		216,434
Segment assets	47,241,054		40,964,520	47,241,054		40,964,520
Intersegment Elimination
Segment Reporting Information [Line Items]
Net Interest income (expense)	(2)		(50)	2		(214)
Provision (reversal) for loan losses	0		0	0		0
Non interest Income	(140)		(146)	(279)		(290)
Amortization of intangibles	0		0	0		0
Depreciation expense	0		0	0		0
Other operating expenses	(137)		(138)	(273)		(276)
Income tax (benefit) expense	0		(23)	0		(93)
Net income (loss)	(5)		(35)	(4)		(135)
Segment assets	(110,936)		(14,533)	(110,936)		(14,533)
Corporate
Segment Reporting Information [Line Items]
Net Interest income (expense)	(14,060)		(14,840)	(28,278)		(29,909)
Provision (reversal) for loan losses	(20)		270	(41)		270
Non interest Income	10,790		10,912	23,738		22,339
Amortization of intangibles	0		0	0		0
Depreciation expense	173		157	360		320
Other operating expenses	22,689		19,275	44,771		39,201
Income tax (benefit) expense	(8,423)		(8,036)	(13,435)		(16,459)
Net income (loss)	(17,689)		(15,594)	(36,195)		(30,902)
Segment assets	5,344,785		5,013,932	5,344,785		5,013,932
Eliminations
Segment Reporting Information [Line Items]
Net Interest income (expense)	0		0	0		0
Provision (reversal) for loan losses	0		(5,955)	0		(5,955)
Non interest Income	(1,170)		(1,317)	(1,448)		(1,394)
Amortization of intangibles	0		0	0		0
Depreciation expense	0		0	0		0
Other operating expenses	(677)		(771)	(1,528)		(1,399)
Income tax (benefit) expense	(188)		2,110	43		2,321
Net income (loss)	(305)		3,299	37		3,639
Segment assets	(5,050,662)		(4,735,783)	(5,050,662)		(4,735,783)
Banco Popular de Puerto Rico | Reportable Segment
Segment Reporting Information [Line Items]
Net Interest income (expense)	352,721		319,667	684,989		629,879
Provision (reversal) for loan losses	44,425		50,373	102,894		80,491
Non interest Income	220,190		102,140	316,815		201,872
Amortization of intangibles	2,158		2,178	4,317		4,357
Depreciation expense	10,406		9,812	20,934		19,545
Other operating expenses	254,921		233,729	495,450		470,030
Income tax (benefit) expense	(24,180)		31,652	1,667		65,650
Net income (loss)	285,181		94,063	376,542		191,678
Segment assets	37,883,250		32,004,896	37,883,250		32,004,896
Banco Popular de Puerto Rico | Commercial Banking | Reportable Segment
Segment Reporting Information [Line Items]
Net Interest income (expense)	145,674		128,364	284,944		248,660
Provision (reversal) for loan losses	9,754		896	30,447		323
Non interest Income	23,930		21,335	36,492		40,763
Amortization of intangibles	51		50	103		104
Depreciation expense	4,341		4,346	8,630		8,608
Other operating expenses	60,639		54,602	120,900		115,435
Income tax (benefit) expense	24,697		26,779	41,572		48,855
Net income (loss)	70,122		63,026	119,784		116,098
Segment assets	26,355,657		19,409,235	26,355,657		19,409,235
Banco Popular de Puerto Rico | Consumer and Retail Banking | Reportable Segment
Segment Reporting Information [Line Items]
Net Interest income (expense)	205,795		189,997	397,229		378,129
Provision (reversal) for loan losses	34,671		49,477	72,447		80,168
Non interest Income	69,967		58,520	131,824		116,591
Amortization of intangibles	1,071		1,073	2,140		2,140
Depreciation expense	5,912		5,285	11,997		10,552
Other operating expenses	172,031		166,694	334,521		327,958
Income tax (benefit) expense	11,732		1,068	19,189		10,051
Net income (loss)	50,345		24,920	88,759		63,851
Segment assets	21,007,705		18,254,883	21,007,705		18,254,883
Banco Popular de Puerto Rico | Other Financial Services | Reportable Segment
Segment Reporting Information [Line Items]
Net Interest income (expense)	1,258		1,295	2,834		3,082
Provision (reversal) for loan losses	0		0	0		0
Non interest Income	23,764		22,346	46,213		44,657
Amortization of intangibles	1,036		1,055	2,074		2,113
Depreciation expense	153		181	307		385
Other operating expenses	14,367		12,505	32,400		26,797
Income tax (benefit) expense	3,279		3,805	4,794		6,744
Net income (loss)	6,187		6,095	9,472		11,700
Segment assets	536,164		468,540	536,164		468,540
Banco Popular de Puerto Rico | Eliminations | Reportable Segment
Segment Reporting Information [Line Items]
Net Interest income (expense)	(6)		11	(18)		8
Provision (reversal) for loan losses	0		0	0		0
Non interest Income	102,529		(61)	102,286		(139)
Amortization of intangibles	0		0	0		0
Depreciation expense	0		0	0		0
Other operating expenses	7,884		(72)	7,629		(160)
Income tax (benefit) expense	(63,888)		0	(63,888)		0
Net income (loss)	158,527	[1]	22	158,527	[1]	29
Segment assets	(10,016,276)		(6,127,762)	(10,016,276)		(6,127,762)
Popular Bank | Reportable Segment
Segment Reporting Information [Line Items]
Net Interest income (expense)	75,477		69,702	150,470		136,821
Provision (reversal) for loan losses	15,649		7,791	28,264		18,371
Non interest Income	5,139		5,204	9,480		10,135
Amortization of intangibles	166		166	332		332
Depreciation expense	2,163		2,160	4,281		4,063
Other operating expenses	45,806		40,267	91,026		81,980
Income tax (benefit) expense	4,231		10,029	5,320		17,319
Net income (loss)	12,601		14,493	30,727		24,891
Segment assets	$ 9,468,740		$ 8,974,157	$ 9,468,740		$ 8,974,157

[1] Includes the impact of the Termination Agreement with the FDIC and the Tax Closing Agreement entered into in connection with the FDIC transaction. These transactions resulted in a gain of $102.8 million reported in the non-interest income line, other operating expenses of $8.1 million and a net tax benefit of $63.9 million. Refer to Notes 9 and 31 to the Consolidated Financial Statements for additional information.