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	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	$ 108,506	$ 146,084	$ 147,252
Less than 12 months Gross Unrealized Losses	1,568	2,594	2,050
12 months or more Fair Value	53,660	64,410	207,638
12 months or more Gross Unrealized Losses	4,918	4,731	8,146
Total Fair Value	162,166	210,494	354,890
Total Gross Unrealized Losses	6,486	7,325	10,196
Obligations of Puerto Rico, States and political subdivisions
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	9,983	19,357
Less than 12 months Gross Unrealized Losses	17	213
12 months or more Fair Value	300	303	305
12 months or more Gross Unrealized Losses	7	5	4
Total Fair Value	10,283	19,660	305
Total Gross Unrealized Losses	24	218	4
Collateralized mortgage obligations - federal agencies
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	27,797	40,212	138,856
Less than 12 months Gross Unrealized Losses	555	945	1,915
12 months or more Fair Value		2,505	114,113
12 months or more Gross Unrealized Losses		2	514
Total Fair Value	27,797	42,717	252,969
Total Gross Unrealized Losses	555	947	2,429
Collateralized mortgage obligations - private label
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	26,268	21,231	200
Less than 12 months Gross Unrealized Losses	652	292	8
12 months or more Fair Value	44,153	52,302	84,564
12 months or more Gross Unrealized Losses	4,561	4,398	7,091
Total Fair Value	70,421	73,533	84,764
Total Gross Unrealized Losses	5,213	4,690	7,099
Mortgage backed securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	31,685	33,261	8,174
Less than 12 months Gross Unrealized Losses	89	406	109
12 months or more Fair Value	9,154	9,257	1,465
12 months or more Gross Unrealized Losses	254	232	52
Total Fair Value	40,839	42,518	9,639
Total Gross Unrealized Losses	343	638	161
Equity securities (without contractual maturity)
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	2,846	3	22
Less than 12 months Gross Unrealized Losses	182	8	18
12 months or more Fair Value	53	43	7,191
12 months or more Gross Unrealized Losses	96	94	485
Total Fair Value	2,899	46	7,213
Total Gross Unrealized Losses	278	102	503
Obligations of U.S. Government sponsored entities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	9,927	24,284
Less than 12 months Gross Unrealized Losses	73	661
Total Fair Value	9,927	24,284
Total Gross Unrealized Losses	73	661
Other
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value		7,736
Less than 12 months Gross Unrealized Losses		69
Total Fair Value		7,736
Total Gross Unrealized Losses		$ 69