DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Notional Amounts and Gross Fair Values (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Notional amount	$ 6,566,893	$ 5,628,119
Derivative asset, not offset against collateral	5,376	1,448
Derivative liability, not offset against collateral	10,907	13,581
Derivative asset, not subject to master netting arrangement	13,371	29,099
Derivative liability, not subject to master netting arrangement	64,134	15,616
Fair value, asset	18,747	30,547
Fair value, liability	75,041	29,197
Interest rate contracts - designated [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, not offset against collateral	0	228
Derivative liability, not offset against collateral	4,760	1,982
Interest rate swaps - not designated [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, not offset against collateral	5,353	1,169
Derivative liability, not offset against collateral	6,147	11,599
Derivative asset, not subject to master netting arrangement	12,214	27,233
Derivative liability, not subject to master netting arrangement	64,006	15,303
Equity contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, not offset against collateral	23	51
Derivative liability, not offset against collateral	0	0
Derivative asset, not subject to master netting arrangement	0	0
Derivative liability, not subject to master netting arrangement	23	51
Interest rate lock commitments – not designated [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, not subject to master netting arrangement	772	1,594
Derivative liability, not subject to master netting arrangement	21	5
Forward delivery commitments – not designated [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, not subject to master netting arrangement	362	233
Derivative liability, not subject to master netting arrangement	33	148
Credit risk contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	121,700
Derivative asset, not subject to master netting arrangement	23	39
Derivative liability, not subject to master netting arrangement	51	109
Subject to Master Netting Arrangements [Member]
Derivatives, Fair Value [Line Items]
Notional amount	3,531,086	2,951,622
Subject to Master Netting Arrangements [Member] \| Interest rate contracts - designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	855,000	705,000
Subject to Master Netting Arrangements [Member] \| Interest rate swaps - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	2,674,906	2,245,442
Subject to Master Netting Arrangements [Member] \| Equity contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	1,180	1,180
Not Subject to Master Netting Arrangements [Member]
Derivatives, Fair Value [Line Items]
Notional amount	3,035,807	2,676,497
Not Subject to Master Netting Arrangements [Member] \| Interest rate swaps - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	2,674,906	2,245,442
Not Subject to Master Netting Arrangements [Member] \| Equity contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	1,180	1,180
Not Subject to Master Netting Arrangements [Member] \| Interest rate lock commitments – not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	67,079	88,107
Not Subject to Master Netting Arrangements [Member] \| Forward delivery commitments – not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	90,861	106,572
Not Subject to Master Netting Arrangements [Member] \| Credit risk contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	$ 201,781	$ 235,196

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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Fair value of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, not subject to a master netting arrangement.

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