OTHER BORROWINGS - Components of Other Borrowings (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Junior Subordinated Debentures Bearing Interest At Floating Rate Of Two Point Seventy Five [Member]
Debt Instrument [Line Items]
Floating Interest rate on junior subordinated debentures	4.35%	3.74%
Subordinated Borrowing Due Date	Jun. 17, 2034
Callable step-rate notes rate	2.75%
Junior Subordinated Debentures Bearing Interest At Floating Rate Of Two Point Fifty Percent [Member]
Debt Instrument [Line Items]
Floating Interest rate on junior subordinated debentures	4.12%	3.50%
Subordinated Borrowing Due Date	Sep. 20, 2034
Callable step-rate notes rate	2.50%