FAIR VALUE MEASUREMENTS - Information about Significant Unobservable Inputs Used for Recurring Fair Value Measurements for Level 3 MSRs (Detail) - Fair Value, Measurements, Recurring - Level 3 - Mortgage Servicing Rights	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Unobservable input, cost to service	$ 83	$ 81
Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Unobservable input, cost to service	108	135
Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Unobservable input, cost to service	$ 98	$ 107
Discount Rate | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
MSR measurement inputs	0.090	0.090
Discount Rate | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
MSR measurement inputs	0.120	0.120
Discount Rate | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
MSR measurement inputs	0.094	0.093
Prepayment Rate | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
MSR measurement inputs	0.193	0.063
Prepayment Rate | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
MSR measurement inputs	0.555	0.266
Prepayment Rate | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
MSR measurement inputs	0.420	0.137
Delinquency Rate | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
MSR measurement inputs	0.000	0.000
Delinquency Rate | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
MSR measurement inputs	0.060	0.040
Delinquency Rate | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
MSR measurement inputs	0.025	0.022