DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Derivative [Line Items]
Notional amount	$ 12,238,000,000		$ 9,558,000,000
Additional amount in excess of posted collateral required in case of breached agreements	$ 300,000		100,000
Interest rate contracts [Member]
Derivative [Line Items]
Maximum length of time hedged in interest rate cash flow hedge	4 years 1 month 6 days
Period to reclassification of cash flow hedge gain loss	12 months
Derivative gains to be reclassified within twelve months	$ 18,700,000
Derivative gains to be reclassified within twelve months, net of tax	14,500,000
Derivative gain or loses excluded from assessment of hedge effectiveness	0
Amount of gain (loss) reclassified from AOCI into net income	0	$ 0
Notional amount	225,000,000.0
Credit risk contracts - not designated [Member]
Derivative [Line Items]
Notional amount	302,500,000
Maximum exposure under credit risk agreement assuming customer default	700,000		300,000
Credit risk derivatives, purchased at fair value	300,000		100,000
Credit risk derivatives, sold at fair value	$ 700,000		$ 300,000
Credit risk contracts - not designated [Member] | Minimum [Member]
Derivative [Line Items]
Risk participation agreements, term	1 month
Credit risk contracts - not designated [Member] | Maximum [Member]
Derivative [Line Items]
Risk participation agreements, term	20 years