DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Derivative [Line Items]
Notional amount	$ 12,702,000,000		$ 12,480,000,000
Additional amount in excess of posted collateral required in case of breached agreements	$ 300,000		300,000
Interest rate contracts [Member]
Derivative [Line Items]
Maximum length of time hedged in interest rate cash flow hedge	3 years 4 months 24 days
Period to reclassification of cash flow hedge gain loss	12 months
Derivative gains to be reclassified within twelve months	$ 17,700,000
Derivative gains to be reclassified within twelve months, net of tax	13,800,000
Derivative gain or losses excluded from assessment of hedge effectiveness	0
Amount of gain (loss) reclassified from AOCI into net income	0	$ 0
Credit risk contracts - not designated [Member]
Derivative [Line Items]
Notional amount	313,100,000
Maximum exposure under credit risk agreement assuming customer default	400,000		600,000
Credit risk derivatives, purchased at fair value	100,000		200,000
Credit risk derivatives, sold at fair value	$ 400,000		$ 600,000
Credit risk contracts - not designated [Member] | Minimum [Member]
Derivative [Line Items]
Risk participation agreements, term	1 year
Credit risk contracts - not designated [Member] | Maximum [Member]
Derivative [Line Items]
Risk participation agreements, term	20 years