CREDIT QUALITY ASSESSMENT (Summary of Impaired Loans) (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Credit Quality Assessment [Abstract]
Impaired loans with a specific allowance	$ 11,446	$ 11,693
Impaired loans without a specific allowance	9,347	9,116
Total impaired loans	20,793	20,809
Allowance for loan and lease losses related to impaired loans	4,479	4,014
Allowance for loan and lease losses related to loans collectively evaluated	42,452	41,243
Total allowance for loan and lease losses	46,931	45,257
Average impaired loans for the period	20,802	23,179
Contractual interest income due on impaired loans during the period	649	2,314
Interest income on impaired loans recognized on a cash basis	111	754
Interest income on impaired loans recognized on an accrual basis	$ 46	$ 169