LEASES - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Jan. 01, 2019
Lessee Lease Description [Line Items]
Operating lease right-of-use assets	$ 10,011,000		$ 10,011,000		$ 12,132,000	$ 7,900,000
Operating lease liabilities	$ 10,318,000		$ 10,318,000		$ 12,423,000	$ 8,200,000
Weighted average discount rate	3.09%		3.09%		3.05%
Weighted average lease term	5 years 11 months 26 days		5 years 11 months 26 days		6 years 3 months 29 days
Operating lease costs	$ 789,000	$ 756,000	$ 2,400,000	$ 2,100,000
Variable lease costs	$ 82,000	$ 83,000	$ 259,000	$ 238,000
Minimum [Member]
Lessee Lease Description [Line Items]
Remaining lease term			3 months		5 months
Maximum [Member]
Lessee Lease Description [Line Items]
Remaining lease term			16 years		17 years
ASU 842 [Member]
Lessee Lease Description [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 01, 2019		Jan. 01, 2019
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true		true
Change in Accounting Principle, Accounting Standards Update, Transition Option Elected [Extensible List]			us-gaap:AccountingStandardsUpdate201602RetrospectiveMember