LOANS AND LEASES - Summary of Payment Status of TDRs (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	$ 48,064	$ 53,991
Originated Loans and Leases [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	44,644	50,183
Acquired Loans [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	3,420	3,808
Performing [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	17,030	19,804
Performing [Member] | Originated Loans and Leases [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	16,963	19,538
Performing [Member] | Acquired Loans [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	67	266
Non-Performing [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	22,322	23,481
Non-Performing [Member] | Originated Loans and Leases [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	19,060	20,173
Non-Performing [Member] | Acquired Loans [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	3,262	3,308
Non-Accrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	8,712	10,706
Non-Accrual [Member] | Originated Loans and Leases [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	8,621	10,472
Non-Accrual [Member] | Acquired Loans [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	$ 91	$ 234