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 - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Unobservable input, discount rate	10.00%	10.00%
Unobservable input, prepayment rate	4.60%	5.10%
Unobservable input, delinquency rate	0.00%	0.00%
Unobservable input, cost to service	$ 84	$ 83
Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Unobservable input, discount rate	15.00%	15.00%
Unobservable input, prepayment rate	22.30%	18.80%
Unobservable input, delinquency rate	13.00%	10.00%
Unobservable input, cost to service	$ 181	$ 152
Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Unobservable input, discount rate	10.40%	10.40%
Unobservable input, prepayment rate	9.40%	8.70%
Unobservable input, delinquency rate	2.20%	2.30%
Unobservable input, cost to service	$ 102	$ 100