LOANS AND LEASES - Summary of Payment Status of TDRs (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	$ 54,192	$ 46,933
Originated Loans and Leases [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	50,422	46,392
Acquired Loans [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	3,770	541
Performing [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	16,853	17,470
Performing [Member] | Originated Loans and Leases [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	16,601	17,105
Performing [Member] | Acquired Loans [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	252	365
Non-Performing [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	23,147	20,428
Non-Performing [Member] | Originated Loans and Leases [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	19,629	20,252
Non-Performing [Member] | Acquired Loans [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	3,518	176
Non-Accrual [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	14,192	9,035
Non-Accrual [Member] | Originated Loans and Leases [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	14,192	9,035
Non-Accrual [Member] | Acquired Loans [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	$ 0	$ 0