LOANS - Summary of Information Pertaining to Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Impaired Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 18,129	$ 17,952	$ 16,813	$ 18,129	$ 16,813	$ 17,952
Troubled debt restructurings not included above	12,952	9,323	11,023	12,952	11,023	9,323
Total impaired loans	31,081	27,275	27,836	31,081	27,836	27,275
Interest income recognized on impaired loans	282	202	185	464	424	827
Foregone interest income on impaired loans	199	217	221	407	411	853
Purchased Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	23,350	24,107	33,557	23,350	33,557	24,107
Troubled debt restructurings not included above	18,430	18,740	20,607	18,430	20,607	18,740
Total impaired loans	41,780	42,847	54,164	41,780	54,164	42,847
Interest income recognized on impaired loans	889	918	280	1,561	976	2,203
Foregone interest income on impaired loans	$ 551	$ 451	$ 280	$ 1,071	$ 525	$ 1,483