DERIVATIVES - Summary of Derivative Financial Instruments and Balances (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Interest-bearing deposit swap	$ 1,674,080	$ 1,354,056
Estimate Fair Value Gain	12,682	12,559
Estimate Fair Value Loss	(12,687)	(12,587)
Fair Value Hedges \| Matched interest rate swaps \| Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Interest-bearing deposit swap	837,040	677,028
Estimate Fair Value Gain	5,529	4,158
Estimate Fair Value Loss	(7,158)	(8,429)
Fair Value Hedges \| Matched interest rate swaps \| Accrued interest and other assets
Derivatives, Fair Value [Line Items]
Interest-bearing deposit swap	837,040	677,028
Estimate Fair Value Gain	7,153	8,401
Estimate Fair Value Loss	$ (5,529)	$ (4,158)

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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+ References

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-Publisher FASB
-Name Accounting Standards Codification
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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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