DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Derivative [Line Items]
Notional amount	$ 5,337,710,000		$ 4,005,212,000
Additional amount in excess of posted collateral required in case of breached agreements	$ 1,300,000		1,100,000
Minimum [Member] | Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Lock in period for interest rates	30 days
Maximum [Member] | Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Lock in period for interest rates	90 days
Interest rate contracts [Member]
Derivative [Line Items]
Period to reclassification of cash flow hedge gain loss	12 months
Maximum length of time hedged in interest rate cash flow hedge	6 years
Derivative gains to be reclassified within twelve months	$ 4,000
Derivative gains to be reclassified within twelve months, net of tax	3,000
Derivative gain or loses excluded from assessment of hedge effectiveness	0
Hedge ineffectiveness	0	$ 0
Gains or losses from cash flow hedge derivatives reclassified to earnings	0	$ 0
Credit Risk Contract Sold [Member]
Derivative [Line Items]
Notional amount	145,400,000.0
Maximum exposure under credit risk agreement assuming customer default	$ 115,000		$ 123,000
Credit Risk Contract Sold [Member] | Minimum [Member]
Derivative [Line Items]
Risk participation agreements, term	5 months
Credit Risk Contract Sold [Member] | Maximum [Member]
Derivative [Line Items]
Risk participation agreements, term	9 years