INVESTMENT SECURITIES - Summary of Amortized Cost and Fair Value (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Securities held-to-maturity:
Amortized Cost	$ 962,282	$ 962,203
Gross Unrealized Gains	26,127	296
Gross Unrealized Losses	(7,538)	(30,214)
Fair Value	980,871	932,285
Securities available-for-sale:
Amortized Cost	1,298,196	838,768
Gross Unrealized Gains	6,065	198
Gross Unrealized Losses	(1,476)	(5,370)
Fair Value	1,302,785	833,596
SBA loan pool securities
Securities available-for-sale:
Amortized Cost	1,363	1,485
Gross Unrealized Gains	53	19
Gross Unrealized Losses	0	0
Fair Value	1,416	1,504
Private label residential mortgage-backed securities
Securities available-for-sale:
Amortized Cost	1,452	1,755
Gross Unrealized Gains	4	14
Gross Unrealized Losses	(3)	(1)
Fair Value	1,453	1,768
Corporate bonds
Securities available-for-sale:
Amortized Cost	60,167	26,657
Gross Unrealized Gains	285	0
Gross Unrealized Losses	(339)	(505)
Fair Value	60,113	26,152
Collateralized loan obligations
Securities available-for-sale:
Amortized Cost	939,215	111,719
Gross Unrealized Gains	4,430	31
Gross Unrealized Losses	(939)	(282)
Fair Value	942,706	111,468
Commercial mortgage-backed securities
Securities available-for-sale:
Amortized Cost	11,186
Gross Unrealized Gains	212
Gross Unrealized Losses	0
Fair Value	11,398
Agency mortgage-backed securities
Securities available-for-sale:
Amortized Cost	284,813	697,152
Gross Unrealized Gains	1,081	134
Gross Unrealized Losses	(195)	(4,582)
Fair Value	285,699	692,704
Corporate bonds
Securities held-to-maturity:
Amortized Cost	239,675	239,274
Gross Unrealized Gains	10,101	255
Gross Unrealized Losses	(572)	(20,946)
Fair Value	249,204	218,583
Collateralized loan obligations
Securities held-to-maturity:
Amortized Cost	416,322	416,284
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(6,692)	(5,077)
Fair Value	409,630	411,207
Commercial mortgage-backed securities
Securities held-to-maturity:
Amortized Cost	306,285	306,645
Gross Unrealized Gains	16,026	41
Gross Unrealized Losses	(274)	(4,191)
Fair Value	$ 322,037	$ 302,495

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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