ACQUISITIONS (Additional Information) (Details) $ in Thousands			12 Months Ended
	Dec. 21, 2018 USD ($) item shares	Jan. 04, 2018 USD ($) item shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Stock options total payment			$ 161
Time deposit discount	$ 1,000	$ 965
Bank-owned life insurance			37,209	$ 35,778
Community Bank of Bergen County Merger
Business Acquisition [Line Items]
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale		$ 261
Branches | item		3
Entity shares issued per acquiree share (in shares) | shares		0.97
Number of shares issued (in shares) | shares		1,873,028
Value of common stock issued		$ 51,900
Cash paid for fractional shares		2
Stock options total payment		140
Merger expenses			$ 0	4,000
Gross amortized cost basis of acquired loans		$ 242,471
Amortization period (in years)		3 years 6 months
Interest rate fair value adjustment on general pooled loans		$ 324
Credit fair value adjustment on general pooled loans		$ (4,100)
Expected term of acquired loans (in years)		4 years
Premium		$ 3,500
Amortization period (in years)		40 years
Life of deposits (in years)		22 months 15 days
Bank-owned life insurance		$ 7,963
Acquired borrowings carrying value		$ 12,000
Community Bank of Bergen County Merger | Weighted Average
Business Acquisition [Line Items]
Life of deposits (in years)		16 months 15 days
Community Bank of Bergen County Merger | Core deposits
Business Acquisition [Line Items]
Useful life (in years)		10 years	10 years
Intangibles		$ 1,300	$ 1,300
Enterprise Bank N.J.
Business Acquisition [Line Items]
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale	$ 100
Branches | item	4
Entity shares issued per acquiree share (in shares) | shares	0.4538
Number of shares issued (in shares) | shares	1,573,454
Value of common stock issued	$ 32,400
Cash paid for fractional shares	1
Stock options total payment	1,600
Merger expenses			0	$ 1,800
Gross amortized cost basis of acquired loans	262,126
Interest rate fair value adjustment on general pooled loans	1,100
Credit fair value adjustment on general pooled loans	$ 3,900
Amortization period (in years)	3 years
Life of deposits (in years)	11 months 12 days
Acquired borrowings carrying value	$ 47,300
Acquired at a discount	$ 282
Weighted average interest rate (in percentage)	2.23%
Fair value adjustment	$ 149
Enterprise Bank N.J. | Weighted Average
Business Acquisition [Line Items]
Life of deposits (in years)	11 months 12 days
Enterprise Bank N.J. | Core deposits
Business Acquisition [Line Items]
Useful life (in years)	10 years
Intangibles	$ 1,000		$ 1,000