CREDIT QUALITY ASSESSMENT (Summary of Impaired Loans) (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Credit Quality Assessment [Abstract]
Impaired loans with a specific allowance	$ 11,450	$ 11,450	$ 11,693
Impaired loans without a specific allowance	6,898	6,898	9,116
Total impaired loans	18,348	18,348	20,809
Allowance for loan and lease losses related to impaired loans	4,204	4,204	4,014
Allowance for loan and lease losses related to loans collectively evaluated	46,205	46,205	41,243
Total allowance for loan and lease losses	50,409	50,409	45,257
Average impaired loans for the period	$ 19,712	19,712	23,179
Contractual interest income due on impaired loans during the period		1,888	2,314
Interest income on impaired loans recognized on a cash basis		473	754
Interest income on impaired loans recognized on an accrual basis		$ 109	$ 169