Note Fair value of financial instruments (Carrying or notional amounts and estimated fair values for financial instruments) (Detail) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Financial Assets:
Cash and due from banks		$ 376,558	$ 394,035
Money market investments		4,814,134	4,171,048
Trading account debt securities, excluding derivatives		39,217	37,787
Debt securities available-for-sale, at fair value		13,542,695	13,300,184
Debt securities held-to-maturity, at amortized cost		99,455	101,575
Equity securities:
Equity securities		158,507	155,584
Loans held in portfolio, net		26,097,080	25,938,541
FDIC loss-share asset				$ 45,659	$ 46,316
Mortgage servicing rights		167,813	169,777	166,281	$ 168,031
Deposits
Time deposits		7,805,764	7,616,764
Total deposits		40,879,838	39,710,039
Assets sold under agreements to repurchase		200,871	281,529
Other short-term borrowings		42	42
Notes payable:
Capital lease obligations		0	20,412
Notes Payable		1,176,488	1,256,102
Contingent consideration			165,000	$ 171,000
Carrying amount
Financial Assets:
Cash and due from banks		376,558	394,035
Money market investments		4,814,134	4,171,048
Trading account debt securities, excluding derivatives	[1]	39,217	37,787
Debt securities available-for-sale, at fair value	[1]	13,542,695	13,300,184
Debt securities held-to-maturity, at amortized cost		99,455	101,575
Equity securities:
FHLB Stock		48,949	51,628
FRB stock		90,598	89,358
Other investments		18,960	14,598
Equity securities		158,507	155,584
Loans held-for-sale		43,985	51,422
Loans held in portfolio, net		26,097,080	25,938,541
Mortgage servicing rights		167,813	169,777
Derivatives		14,843	13,603
Deposits
Demand deposits		33,074,074	32,093,274
Time deposits		7,805,764	7,616,765
Total deposits		40,879,838	39,710,039
Assets sold under agreements to repurchase		200,871	281,529
Other short-term borrowings	[2]	42	42
Notes payable:
Advances with the FHLB		497,250	556,776
Unsecured senior debt securities		294,356	294,039
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust		384,882	384,875
Capital lease obligations			20,412
Notes Payable		1,176,488	1,256,102
Derivatives		12,770	12,320
Fair Value
Financial Assets:
Cash and due from banks		376,558	394,035
Money market investments		4,814,134	4,171,048
Trading account debt securities, excluding derivatives	[1]	39,217	37,787
Debt securities available-for-sale, at fair value	[1]	13,542,695	13,300,184
Debt securities held-to-maturity, at amortized cost		103,457	102,653
Equity securities:
FHLB Stock		48,949	51,628
FRB stock		90,598	89,358
Other investments		24,003	18,835
Equity securities		163,550	159,821
Loans held-for-sale		45,085	52,474
Loans held in portfolio, net		23,941,120	23,143,027
Mortgage servicing rights		167,813	169,777
Derivatives		14,843	13,603
Deposits
Demand deposits		33,074,074	32,093,274
Time deposits		7,633,195	7,392,698
Total deposits		40,707,269	39,485,972
Assets sold under agreements to repurchase		200,691	281,535
Other short-term borrowings	[2]	42	42
Notes payable:
Advances with the FHLB		498,220	553,111
Unsecured senior debt securities		308,142	302,664
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust		389,331	381,079
Capital lease obligations			20,412
Notes Payable		1,195,693	1,257,266
Derivatives		12,770	12,320
Obligations of Puerto Rico, States and political subdivisions
Financial Assets:
Debt securities held-to-maturity, at amortized cost		87,341	89,459
Obligations of Puerto Rico, States and political subdivisions | Carrying amount
Financial Assets:
Debt securities held-to-maturity, at amortized cost		87,341	89,459
Obligations of Puerto Rico, States and political subdivisions | Fair Value
Financial Assets:
Debt securities held-to-maturity, at amortized cost		91,340	90,534
Collateralized Mortgage Obligations - Federal agencies
Financial Assets:
Debt securities held-to-maturity, at amortized cost		53	55
Collateralized Mortgage Obligations - Federal agencies | Carrying amount
Financial Assets:
Debt securities held-to-maturity, at amortized cost		53	55
Collateralized Mortgage Obligations - Federal agencies | Fair Value
Financial Assets:
Debt securities held-to-maturity, at amortized cost		56	58
Securities in wholly owned statutory business trusts
Financial Assets:
Debt securities held-to-maturity, at amortized cost		11,561	11,561
Securities in wholly owned statutory business trusts | Carrying amount
Financial Assets:
Debt securities held-to-maturity, at amortized cost		11,561	11,561
Securities in wholly owned statutory business trusts | Fair Value
Financial Assets:
Debt securities held-to-maturity, at amortized cost		11,561	11,561
Other
Financial Assets:
Debt securities held-to-maturity, at amortized cost		500	500
Other | Carrying amount
Financial Assets:
Debt securities held-to-maturity, at amortized cost		500	500
Other | Fair Value
Financial Assets:
Debt securities held-to-maturity, at amortized cost		500	500
Level 1
Financial Assets:
Cash and due from banks		376,558	394,035
Money market investments		4,804,949	4,161,832
Trading account debt securities, excluding derivatives	[1]	6,764	6,278
Debt securities available-for-sale, at fair value	[1]	2,476,890	2,719,740
Debt securities held-to-maturity, at amortized cost		0	0
Equity securities:
FHLB Stock		0	0
FRB stock		0	0
Other investments		0	0
Equity securities		0	0
Loans held-for-sale		0	0
Loans held in portfolio, net		0	0
Mortgage servicing rights		0	0
Derivatives		0	0
Deposits
Demand deposits		0	0
Time deposits		0	0
Total deposits		0	0
Assets sold under agreements to repurchase		0	0
Other short-term borrowings	[2]	0	0
Notes payable:
Advances with the FHLB		0	0
Unsecured senior debt securities		0	0
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust		0	0
Capital lease obligations		0	0
Notes Payable		0	0
Derivatives		0	0
Level 1 | Obligations of Puerto Rico, States and political subdivisions
Financial Assets:
Debt securities held-to-maturity, at amortized cost		0	0
Level 1 | Collateralized Mortgage Obligations - Federal agencies
Financial Assets:
Debt securities held-to-maturity, at amortized cost		0	0
Level 1 | Securities in wholly owned statutory business trusts
Financial Assets:
Debt securities held-to-maturity, at amortized cost		0	0
Level 1 | Other
Financial Assets:
Debt securities held-to-maturity, at amortized cost		0	0
Level 2
Financial Assets:
Cash and due from banks		0	0
Money market investments		9,185	9,216
Trading account debt securities, excluding derivatives	[1]	31,337	30,370
Debt securities available-for-sale, at fair value	[1]	11,064,570	10,579,211
Debt securities held-to-maturity, at amortized cost		12,061	12,061
Equity securities:
FHLB Stock		48,949	51,628
FRB stock		90,598	89,358
Other investments		17,658	13,296
Equity securities		157,205	154,282
Loans held-for-sale		0	0
Loans held in portfolio, net		0	0
Mortgage servicing rights		0	0
Derivatives		14,843	13,603
Deposits
Demand deposits		33,074,074	32,093,274
Time deposits		7,633,195	7,392,698
Total deposits		40,707,269	39,485,972
Assets sold under agreements to repurchase		200,691	281,535
Other short-term borrowings	[2]	42	42
Notes payable:
Advances with the FHLB		498,220	553,111
Unsecured senior debt securities		308,142	302,664
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust		389,331	381,079
Capital lease obligations			0
Notes Payable		1,195,693	1,236,854
Derivatives		12,770	12,320
Level 2 | Obligations of Puerto Rico, States and political subdivisions
Financial Assets:
Debt securities held-to-maturity, at amortized cost		0	0
Level 2 | Collateralized Mortgage Obligations - Federal agencies
Financial Assets:
Debt securities held-to-maturity, at amortized cost		0	0
Level 2 | Securities in wholly owned statutory business trusts
Financial Assets:
Debt securities held-to-maturity, at amortized cost		11,561	11,561
Level 2 | Other
Financial Assets:
Debt securities held-to-maturity, at amortized cost		500	500
Level 3
Financial Assets:
Cash and due from banks		0	0
Money market investments		0	0
Trading account debt securities, excluding derivatives	[1]	1,116	1,139
Debt securities available-for-sale, at fair value	[1]	1,235	1,233
Debt securities held-to-maturity, at amortized cost		91,396	90,592
Equity securities:
FHLB Stock		0	0
FRB stock		0	0
Other investments		6,345	5,539
Equity securities		6,345	5,539
Loans held-for-sale		45,085	52,474
Loans held in portfolio, net		23,941,120	23,143,027
Mortgage servicing rights		167,813	169,777
Derivatives		0	0
Deposits
Demand deposits		0	0
Time deposits		0	0
Total deposits		0	0
Assets sold under agreements to repurchase		0	0
Other short-term borrowings	[2]	0	0
Notes payable:
Advances with the FHLB		0	0
Unsecured senior debt securities		0	0
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust		0	0
Capital lease obligations			20,412
Notes Payable		0	20,412
Derivatives		0	0
Level 3 | Obligations of Puerto Rico, States and political subdivisions
Financial Assets:
Debt securities held-to-maturity, at amortized cost		91,340	90,534
Level 3 | Collateralized Mortgage Obligations - Federal agencies
Financial Assets:
Debt securities held-to-maturity, at amortized cost		56	58
Level 3 | Securities in wholly owned statutory business trusts
Financial Assets:
Debt securities held-to-maturity, at amortized cost		0	0
Level 3 | Other
Financial Assets:
Debt securities held-to-maturity, at amortized cost		$ 0	$ 0

[1] Refer to Note 24 to the C onsolidated F inancial S tatements for the fair value by class of financial asset and its hierarchy level.

[2] Refer to Note 17 to the Consolidated F inancial S tatements for the composition of other short-term borrowings.