Assets and liabilities measured at fair value on a recurring basis (Detail) - Entity [Domain] - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Assets
Available For Sale Securities		$ 5,585,078	$ 5,315,159
Trading Securities		141,595	138,527
Mortgage servicing rights		206,357	148,694	$ 151,951	$ 161,099
Derivatives		21,716	25,362
US Treasury Securities [Member]
Assets
Available For Sale Securities		973,723	700,154
US Government Sponsored Enterprises Debt Securities Member
Assets
Available For Sale Securities		1,110,372	1,724,973
Puerto Rico States And Political Subdivisions Debt Securities [Member]
Assets
Available For Sale Securities		52,114	61,712
Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Assets
Available For Sale Securities		1,736,829	1,910,030
Collateralized Mortgage Obligations Issued By Private Enterprise [Member]
Assets
Available For Sale Securities		0	0
Collateralized Mortgage Backed Securities [Member]
Assets
Available For Sale Securities		1,698,844	904,362
Equity Securities [Member]
Assets
Available For Sale Securities		2,594	2,622
Other Securities [Member]
Assets
Available For Sale Securities		10,602	11,306
Fair Value, Inputs, Level 1 [Member]
Assets
Available For Sale Securities	[1]	310	323
Trading Securities	[1]	0	0
Mortgage servicing rights		0	0
Derivatives		0	0
Liabilities
Derivative Financial Instruments Liabilities Fair Value Disclosure		0	0
Business Combination Contingent Consideration Liability		0	0
Fair Value, Inputs, Level 2 [Member]
Assets
Available For Sale Securities	[1]	5,583,323	5,313,511
Trading Securities	[1]	132,738	129,360
Mortgage servicing rights		0	0
Derivatives		21,716	25,362
Liabilities
Derivative Financial Instruments Liabilities Fair Value Disclosure		18,430	23,032
Business Combination Contingent Consideration Liability		0	0
Fair Value, Inputs, Level 3 [Member]
Assets
Available For Sale Securities	[1]	1,445	1,325
Trading Securities	[1]	8,857	9,167
Mortgage servicing rights		206,357	148,694
Derivatives		0	0
Liabilities
Derivative Financial Instruments Liabilities Fair Value Disclosure		0	0
Business Combination Contingent Consideration Liability		124,837	133,634
Fair Value, Measurements, Recurring [Member]
Assets
Available For Sale Securities		5,585,078	5,315,159
Trading Securities		141,595	138,527
Mortgage servicing rights		206,357	148,694
Derivatives		21,716	25,362
Total		5,954,746	5,627,742
Liabilities
Derivative Financial Instruments Liabilities Fair Value Disclosure		(18,430)	(23,032)
Business Combination Contingent Consideration Liability		(124,837)	(133,634)
Total		(143,267)	(156,666)
Fair Value, Measurements, Recurring [Member] | US Treasury Securities [Member]
Assets
Available For Sale Securities		973,723	700,154
Fair Value, Measurements, Recurring [Member] | US Government Sponsored Enterprises Debt Securities Member
Assets
Available For Sale Securities		1,110,372	1,724,973
Fair Value, Measurements, Recurring [Member] | Puerto Rico States And Political Subdivisions Debt Securities [Member]
Assets
Available For Sale Securities		52,114	61,712
Trading Securities		5,614	7,954
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Assets
Available For Sale Securities		1,736,829	1,910,030
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Obligations Issued By Private Enterprise [Member]
Assets
Available For Sale Securities		0	0
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member]
Assets
Available For Sale Securities		1,698,844	904,362
Trading Securities		117,185	110,692
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Assets
Available For Sale Securities		2,594	2,622
Fair Value, Measurements, Recurring [Member] | Other Securities [Member]
Assets
Available For Sale Securities		10,602	11,306
Trading Securities		17,369	18,245
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Obligations Member
Assets
Trading Securities		1,427	1,636
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets
Available For Sale Securities		310	323
Trading Securities		0	0
Mortgage servicing rights		0	0
Derivatives		0	0
Total		310	323
Liabilities
Derivative Financial Instruments Liabilities Fair Value Disclosure		0	0
Business Combination Contingent Consideration Liability		0	0
Total		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Assets
Available For Sale Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Government Sponsored Enterprises Debt Securities Member
Assets
Available For Sale Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Puerto Rico States And Political Subdivisions Debt Securities [Member]
Assets
Available For Sale Securities		0	0
Trading Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Assets
Available For Sale Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Collateralized Mortgage Obligations Issued By Private Enterprise [Member]
Assets
Available For Sale Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Collateralized Mortgage Backed Securities [Member]
Assets
Available For Sale Securities		0	0
Trading Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Assets
Available For Sale Securities		310	323
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other Securities [Member]
Assets
Available For Sale Securities		0	0
Trading Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Collateralized Mortgage Obligations Member
Assets
Trading Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets
Available For Sale Securities		5,583,323	5,313,511
Trading Securities		132,738	129,360
Mortgage servicing rights		0	0
Derivatives		21,716	25,362
Total		5,737,777	5,468,233
Liabilities
Derivative Financial Instruments Liabilities Fair Value Disclosure		(18,430)	(23,032)
Business Combination Contingent Consideration Liability		0	0
Total		(18,430)	(23,032)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]
Assets
Available For Sale Securities		973,723	700,154
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US Government Sponsored Enterprises Debt Securities Member
Assets
Available For Sale Securities		1,110,372	1,724,973
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Puerto Rico States And Political Subdivisions Debt Securities [Member]
Assets
Available For Sale Securities		52,114	61,712
Trading Securities		5,614	7,954
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Assets
Available For Sale Securities		1,736,829	1,910,030
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Collateralized Mortgage Obligations Issued By Private Enterprise [Member]
Assets
Available For Sale Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Collateralized Mortgage Backed Securities [Member]
Assets
Available For Sale Securities		1,697,399	903,037
Trading Securities		111,139	104,463
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Assets
Available For Sale Securities		2,284	2,299
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other Securities [Member]
Assets
Available For Sale Securities		10,602	11,306
Trading Securities		15,750	16,682
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Collateralized Mortgage Obligations Member
Assets
Trading Securities		235	261
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets
Available For Sale Securities		1,445	1,325
Trading Securities		8,857	9,167
Mortgage servicing rights		206,357	148,694
Derivatives		0	0
Total		216,659	159,186
Liabilities
Derivative Financial Instruments Liabilities Fair Value Disclosure		0	0
Business Combination Contingent Consideration Liability		(124,837)	(133,634)
Total		(124,837)	(133,634)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US Treasury Securities [Member]
Assets
Available For Sale Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US Government Sponsored Enterprises Debt Securities Member
Assets
Available For Sale Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Puerto Rico States And Political Subdivisions Debt Securities [Member]
Assets
Available For Sale Securities		0	0
Trading Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Assets
Available For Sale Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Collateralized Mortgage Obligations Issued By Private Enterprise [Member]
Assets
Available For Sale Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Collateralized Mortgage Backed Securities [Member]
Assets
Available For Sale Securities		1,445	1,325
Trading Securities		6,046	6,229
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Assets
Available For Sale Securities		0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other Securities [Member]
Assets
Available For Sale Securities		0	0
Trading Securities		1,619	1,563
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Collateralized Mortgage Obligations Member
Assets
Trading Securities		$ 1,192	$ 1,375

[1] Refer to Note 38 to the consolidated financial statements for the fair value by class of financial asset and its hierarchy level.