INVESTMENT SECURITIES - Contractual Maturity Schedule (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Amortized Cost
Within one year	$ 0
One to five years	0
Five to ten years	186,438
Greater than ten years	52,641
Collateralized loan obligations, SBA loan pool, private label residential mortgage-backed, commercial mortgage-backed, and agency mortgage-backed securities	290,453
Amortized Cost	529,532	$ 0
Fair Value
Within one year	0
One to five years	0
Five to ten years	184,615
Greater than ten years	52,420
Collateralized loan obligations, SBA loan pool, private label residential mortgage-backed, commercial mortgage-backed, and agency mortgage-backed securities	289,923
Total	526,958
Amortized Cost
Within one year	0
One to five years	1,949
Five to ten years	26,662
Greater than ten years	0
Collateralized loan obligations, SBA loan pool, private label residential mortgage-backed, commercial mortgage-backed, and agency mortgage-backed securities	661,932
Amortized Cost	690,543	344,878
Fair Value
Within one year	0
One to five years	2,001
Five to ten years	26,247
Greater than ten years	0
Collateralized loan obligations, SBA loan pool, private label residential mortgage-backed, commercial mortgage-backed, and agency mortgage-backed securities	664,971
Total	$ 693,219	$ 345,695

Held-to-maturity Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]

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Held-to-maturity Securities, Debt Maturities, Next Rolling Twelve Months, Amortized Cost

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Held-to-maturity Securities, Debt Maturities, Rolling Year Six Through Ten, Amortized Cost

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Held-to-maturity Securities, Debt Maturities, Rolling Year Two Through Five, Amortized Cost

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Held-to-maturity Securities, Debt Maturities, Rolling after Ten Years, Amortized Cost

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This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Section S99

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Amount after adjustments of available-for-sale debt securities at cost, maturing in the next rolling twelve months following the latest balance sheet. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments and fair value hedge accounting adjustments. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the next rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, maturing after the tenth rolling twelve months following the latest balance sheet. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing after the tenth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, maturing in the sixth through tenth rolling twelve months following the latest balance sheet. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the sixth through tenth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, maturing in the second through fifth rolling twelve months following the latest balance sheet. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the second through fifth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of available-for-sale debt securities at cost, net of adjustments, that do not have a single maturity date and which the entity has decided to disclose separately rather than allocating the cost over several maturity groupings. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of available-for-sale debt securities at fair value that do not have a single maturity date and which the entity has decided to disclose separately rather than allocating the fair value over several maturity groupings.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Fair value of held-to-maturity debt securities maturing in the next rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of held-to-maturity debt securities maturing in the sixth through tenth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of held-to-maturity debt securities maturing in the second through fifth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of held-to-maturity debt securities at fair value that do not have a single maturity date and which the entity has decided to disclose separately rather than allocating the fair value over several maturity groupings.

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Carrying amount of debt securities accounted for as held-to-maturity, net of adjustments including, but not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized, and fair value hedge accounting adjustments, over several maturity groupings.

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Fair value of investments in debt securities classified as held-to-maturity.

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