LOANS AND LEASES (Additional Information) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Loans and Leases [Abstract]
Unearned income and deferred fees	$ 1,000		$ 1,000		$ 1,800
Loans receivable with a gross amortized cost basis				$ 1,697,760
Credit fair value adjustment on purchased credit impaired loans				10,652
Certain Loans Acquired In Transfer Accretable Yield				2,616
Credit Impaired Loans Acquired In Transfer Nonaccretable Difference				8,100
Outstanding balance of purchased credit impaired loans receivable	16,025		16,025	28,800
Fair value of purchase credit impaired loans	8,000		8,000	$ 18,193
(Decrease) in goodwill from re-measurement period adjustment		$ 3,400
Proceeds from credit impaired loans	$ 10,400
Accreditable adjustments			694
Non-accredtable adjustments			$ 1,300