Fair value and gross unrealized losses of investment securities available-for-sale, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	$ 1,344,907	$ 3,055,888
Less than 12 months Gross Unrealized Losses	36,030	119,453
12 months or more Fair Value	1,302,922	190,985
12 months or more Gross Unrealized Losses	46,265	10,981
Total Fair Value	2,647,829	3,246,873
Total Gross Unrealized Losses	82,295	130,434
US Government Sponsored Enterprises Debt Securities Member
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	594,695	1,326,866
Less than 12 months Gross Unrealized Losses	8,886	32,457
12 months or more Fair Value	462,222	69,257
12 months or more Gross Unrealized Losses	8,247	4,240
Total Fair Value	1,056,917	1,396,123
Total Gross Unrealized Losses	17,133	36,697
Puerto Rico States And Political Subdivisions Debt Securities [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	20,733	54,256
Less than 12 months Gross Unrealized Losses	2,584	11,685
12 months or more Fair Value	24,596	8,330
12 months or more Gross Unrealized Losses	6,241	190
Total Fair Value	45,329	62,586
Total Gross Unrealized Losses	8,825	11,875
Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	713,604	1,567,654
Less than 12 months Gross Unrealized Losses	24,114	70,378
12 months or more Fair Value	758,570	96,676
12 months or more Gross Unrealized Losses	29,430	5,645
Total Fair Value	1,472,174	1,664,330
Total Gross Unrealized Losses	53,544	76,023
Collateralized Mortgage Obligations Issued By Private Enterprise [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	0	0
Less than 12 months Gross Unrealized Losses	0	0
12 months or more Fair Value	0	0
12 months or more Gross Unrealized Losses	0	0
Total Fair Value	0	0
Total Gross Unrealized Losses	0	0
Collateralized Mortgage Backed Securities [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	15,875	105,455
Less than 12 months Gross Unrealized Losses	446	4,762
12 months or more Fair Value	46,384	7,225
12 months or more Gross Unrealized Losses	2,214	765
Total Fair Value	62,259	112,680
Total Gross Unrealized Losses	2,660	5,527
Equity Securities [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	0	1,657
Less than 12 months Gross Unrealized Losses	0	171
12 months or more Fair Value	1,707	0
12 months or more Gross Unrealized Losses	118	0
Total Fair Value	1,707	1,657
Total Gross Unrealized Losses	118	171
Other Securities [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	0	0
Less than 12 months Gross Unrealized Losses	0	0
12 months or more Fair Value	9,443	9,497
12 months or more Gross Unrealized Losses	15	141
Total Fair Value	9,443	9,497
Total Gross Unrealized Losses	$ 15	$ 141