DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Notional Amounts and Gross Fair Values (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Notional amount	$ 5,337,710	$ 4,005,212
Fair value, asset	44,159	54,220
Fair value, liability	25,857	47,267
Interest rate lock commitments – not designated [Member]
Derivatives, Fair Value [Line Items]
Fair value, asset	5,437
Forward delivery commitments – not designated [Member]
Derivatives, Fair Value [Line Items]
Fair value, asset	574
Credit risk contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Fair value, asset	26	13
Subject to Master Netting Arrangements [Member]
Derivatives, Fair Value [Line Items]
Notional amount	2,720,458	2,140,337
Fair value, asset	1,360	22,037
Fair value, liability	14,952	35,217
Subject to Master Netting Arrangements [Member] \| Interest rate contracts - designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	705,000	450,000
Fair value, asset	862	9,256
Fair value, liability	1,194	1,171
Subject to Master Netting Arrangements [Member] \| Interest rate swaps - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	2,014,278	1,689,157
Fair value, asset	472	12,720
Fair value, liability	13,758	34,046
Subject to Master Netting Arrangements [Member] \| Equity contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	1,180	1,180
Fair value, asset	26	61
Fair value, liability	0	0
Not Subject to Master Netting Arrangements [Member]
Derivatives, Fair Value [Line Items]
Notional amount	2,617,252	1,864,875
Fair value, asset	42,799	32,183
Fair value, liability	10,905	12,050
Not Subject to Master Netting Arrangements [Member] \| Interest rate lock commitments – not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	187,375	0
Fair value, asset	5,437	0
Fair value, liability	14	0
Not Subject to Master Netting Arrangements [Member] \| Forward delivery commitments – not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	206,853	0
Fair value, asset	574	0
Fair value, liability	357	0
Not Subject to Master Netting Arrangements [Member] \| Interest rate swaps - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	2,014,278	1,689,157
Fair value, asset	36,762	32,170
Fair value, liability	10,393	11,866
Not Subject to Master Netting Arrangements [Member] \| Equity contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	1,180	1,180
Fair value, asset	0	0
Fair value, liability	26	61
Not Subject to Master Netting Arrangements [Member] \| Credit risk contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	207,566	174,538
Fair value, asset	26	13
Fair value, liability	$ 115	$ 123

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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-Name Accounting Standards Codification
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-Section 45
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+ References

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