INVESTMENT SECURITIES - Investment Securities Held to Maturity (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule Of Held To Maturity Securities [Line Items]
Investment securities held to maturity at amortized cost (fair value 2018 - $125,658; 2017 - $131,032)	$ 144,815	$ 150,627
Held to Maturity Fair value	125,658	131,032
Municipal Bonds [Member] \| Puerto Rico [Member]
Schedule Of Held To Maturity Securities [Line Items]
Held to Maturity Amortized Cost After 1 to 5 years	6,100	3,853
Held to Maturity Gross Unrecognized gains After 1 to 5 years	0	0
Held to Maturity Gross Unrecognized losses After 1 to 5 years	435	173
Held to Maturity Fair value After 1 to 5 years	$ 5,665	$ 3,680
Held to Maturity Weighted-average yield After 1 to 5 years	4.79%	5.38%
Held to Maturity Amortized Cost After 5 to 10 years	$ 53,016	$ 39,523
Held to Maturity Gross Unrecognized gains After 5 to 10 yearss	0	0
Held to Maturity Gross Unrecognized losses After 5 to 10 years	5,360	3,048
Held to Maturity Fair value After 5 to 10 years	$ 47,656	$ 36,475
Held to Maturity Weighted-average yield After 5 to 10 years	6.00%	5.28%
Held to Maturity Amortized Cost After 10 years	$ 85,699	$ 107,251
Held to Maturity Gross Unrecognized gains After 10 years	0	0
Held to Maturity Gross Unrecognized losses After 10 years	13,362	16,374
Held to Maturity Fair value After 10 years	$ 72,337	$ 90,877
Held to Maturity Weighted-average yield After 10 years	5.86%	4.93%
Investment securities held to maturity at amortized cost (fair value 2018 - $125,658; 2017 - $131,032)	$ 144,815	$ 150,627
Held to Maturity Gross Unrecognized gains	0	0
Held to Maturity Gross Unrecognized losses	19,157	19,595
Held to Maturity Fair value	$ 125,658	$ 131,032
Held to Maturity Weighted-average yield	5.86%	5.03%

Weighted average yield of investment in debt security measured at amortized cost (held-to-maturity).

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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing in next fiscal year through fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing after tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing in next fiscal year through fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing after tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Weighted average yield of investment in debt security measured at amortized cost (held-to-maturity), maturing after tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Weighted average yield of investment in debt security measured at amortized cost (held-to-maturity), maturing in sixth through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Weighted average yield of investment in debt security measured at amortized cost (held-to-maturity), maturing in second through fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amount of investment in debt security measured at amortized cost (held-to-maturity).

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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

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Fair value of investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amount of investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Fair value of investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing in next fiscal year through fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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