Amortized cost, gross unrealized gains and losses, approximate fair value, weighted average yield and contractual maturities of investment securities available-for-sale (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 5,649,672	$ 5,345,877
Gross Unrealized Gains	86,615	79,357
Gross Unrealized Losses	82,295	130,434
Investment securities available-for-sale, at fair value	5,653,992	5,294,800
Weighted Average Yield	2.14%	2.30%
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	26,085	26,474
Gross Unrealized Gains	1,644	2,008
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	27,729	28,482
Weighted Average Yield	3.87%	3.85%
US Treasury Securities [Member] | Within One Year From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	0	0
Weighted Average Yield	0.00%	0.00%
US Treasury Securities [Member] | More Than One And Within Five Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	26,085	26,474
Gross Unrealized Gains	1,644	2,008
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	27,729	28,482
Weighted Average Yield	3.87%	3.85%
US Treasury Securities [Member] | More Than Five And Within Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	0	0
Weighted Average Yield	0.00%	0.00%
US Treasury Securities [Member] | More Than Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	0	0
Weighted Average Yield	0.00%	0.00%
US Government Sponsored Enterprises Debt Securities Member
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,231,351	1,664,085
Gross Unrealized Gains	3,012	1,817
Gross Unrealized Losses	17,133	36,697
Investment securities available-for-sale, at fair value	2,217,230	1,629,205
Weighted Average Yield	1.27%	1.38%
US Government Sponsored Enterprises Debt Securities Member | Within One Year From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,998	25,021
Gross Unrealized Gains	7	39
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	7,005	25,060
Weighted Average Yield	0.14%	1.85%
US Government Sponsored Enterprises Debt Securities Member | More Than One And Within Five Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,948,833	1,087,453
Gross Unrealized Gains	2,424	1,678
Gross Unrealized Losses	9,053	12,715
Investment securities available-for-sale, at fair value	1,942,204	1,076,416
Weighted Average Yield	1.20%	1.26%
US Government Sponsored Enterprises Debt Securities Member | More Than Five And Within Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	252,520	528,611
Gross Unrealized Gains	581	100
Gross Unrealized Losses	7,198	21,742
Investment securities available-for-sale, at fair value	245,903	506,969
Weighted Average Yield	1.63%	1.52%
US Government Sponsored Enterprises Debt Securities Member | More Than Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,000	23,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	882	2,240
Investment securities available-for-sale, at fair value	22,118	20,760
Weighted Average Yield	3.15%	3.12%
Puerto Rico States And Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	77,548	78,178
Gross Unrealized Gains	448	74
Gross Unrealized Losses	8,825	11,875
Investment securities available-for-sale, at fair value	69,171	66,377
Weighted Average Yield	5.52%	5.89%
Puerto Rico States And Political Subdivisions Debt Securities [Member] | Within One Year From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	0	0
Weighted Average Yield	0.00%	0.00%
Puerto Rico States And Political Subdivisions Debt Securities [Member] | More Than One And Within Five Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,384	6,228
Gross Unrealized Gains	19	45
Gross Unrealized Losses	22	85
Investment securities available-for-sale, at fair value	5,381	6,188
Weighted Average Yield	2.86%	4.64%
Puerto Rico States And Political Subdivisions Debt Securities [Member] | More Than Five And Within Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,352	23,147
Gross Unrealized Gains	7	0
Gross Unrealized Losses	1,398	1,978
Investment securities available-for-sale, at fair value	21,961	21,169
Weighted Average Yield	5.46%	6.33%
Puerto Rico States And Political Subdivisions Debt Securities [Member] | More Than Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	48,812	48,803
Gross Unrealized Gains	422	29
Gross Unrealized Losses	7,405	9,812
Investment securities available-for-sale, at fair value	41,829	39,020
Weighted Average Yield	5.85%	5.84%
Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,337,854	2,474,765
Gross Unrealized Gains	19,162	19,554
Gross Unrealized Losses	53,544	76,023
Investment securities available-for-sale, at fair value	2,303,472	2,418,296
Weighted Average Yield	2.07%	2.06%
Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member] | Within One Year From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	0	0
Weighted Average Yield	0.00%	0.00%
Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member] | More Than One And Within Five Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,876	5,131
Gross Unrealized Gains	124	101
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	5,000	5,232
Weighted Average Yield	2.56%	1.79%
Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member] | More Than Five And Within Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27,924	31,613
Gross Unrealized Gains	1,219	921
Gross Unrealized Losses	2	0
Investment securities available-for-sale, at fair value	29,141	32,534
Weighted Average Yield	2.82%	2.98%
Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member] | More Than Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,305,054	2,438,021
Gross Unrealized Gains	17,819	18,532
Gross Unrealized Losses	53,542	76,023
Investment securities available-for-sale, at fair value	2,269,331	2,380,530
Weighted Average Yield	2.06%	2.05%
Collateralized Mortgage Obligations Issued By Private Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	130	509
Gross Unrealized Gains	0	4
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	130	513
Weighted Average Yield	3.90%	3.78%
Collateralized Mortgage Obligations Issued By Private Enterprise [Member] | Within One Year From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	0	0
Weighted Average Yield	0.00%	0.00%
Collateralized Mortgage Obligations Issued By Private Enterprise [Member] | More Than One And Within Five Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	0	0
Weighted Average Yield	0.00%	0.00%
Collateralized Mortgage Obligations Issued By Private Enterprise [Member] | More Than Five And Within Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	0	0
Weighted Average Yield	0.00%	0.00%
Collateralized Mortgage Obligations Issued By Private Enterprise [Member] | More Than Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	130	509
Gross Unrealized Gains	0	4
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	130	513
Weighted Average Yield	3.90%	3.78%
Collateralized Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	961,728	1,086,446
Gross Unrealized Gains	60,980	54,722
Gross Unrealized Losses	2,660	5,527
Investment securities available-for-sale, at fair value	1,020,048	1,135,641
Weighted Average Yield	3.97%	3.95%
Collateralized Mortgage Backed Securities [Member] | Within One Year From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1	419
Gross Unrealized Gains	0	24
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	1	443
Weighted Average Yield	3.66%	3.14%
Collateralized Mortgage Backed Securities [Member] | More Than One And Within Five Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	26,420	15,921
Gross Unrealized Gains	1,458	833
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	27,878	16,754
Weighted Average Yield	4.56%	4.50%
Collateralized Mortgage Backed Securities [Member] | More Than Five And Within Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	200,182	62,373
Gross Unrealized Gains	8,743	3,058
Gross Unrealized Losses	486	1,214
Investment securities available-for-sale, at fair value	208,439	64,217
Weighted Average Yield	3.47%	4.12%
Collateralized Mortgage Backed Securities [Member] | More Than Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	735,125	1,007,733
Gross Unrealized Gains	50,779	50,807
Gross Unrealized Losses	2,174	4,313
Investment securities available-for-sale, at fair value	783,730	1,054,227
Weighted Average Yield	4.08%	3.93%
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,177	3,178
Gross Unrealized Gains	1,284	1,109
Gross Unrealized Losses	118	171
Investment securities available-for-sale, at fair value	4,343	4,116
Weighted Average Yield	6.39%	4.06%
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11,799	12,242
Gross Unrealized Gains	85	69
Gross Unrealized Losses	15	141
Investment securities available-for-sale, at fair value	11,869	12,170
Weighted Average Yield	2.06%	2.09%
Other Securities [Member] | Within One Year From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	0	0
Weighted Average Yield	0.00%	0.00%
Other Securities [Member] | More Than One And Within Five Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,458	9,638
Gross Unrealized Gains	0	0
Gross Unrealized Losses	15	141
Investment securities available-for-sale, at fair value	9,443	9,497
Weighted Average Yield	1.68%	1.68%
Other Securities [Member] | More Than Five And Within Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	0	0
Weighted Average Yield	0.00%	0.00%
Other Securities [Member] | More Than Ten Years From Balance Sheet Date [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,341	2,604
Gross Unrealized Gains	85	69
Gross Unrealized Losses	0	0
Investment securities available-for-sale, at fair value	$ 2,426	$ 2,673
Weighted Average Yield	3.63%	3.61%