FAIR VALUE - Carrying Amounts and Estimated Fair Values of Other Financial Instruments (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Financial assets:
Cash and due from financial institutions	$ 30,837,000	$ 27,966,000
Interest-earning deposits in other financial institutions	3,978,000	2,763,000
Securities available for sale	265,157,000	293,091,000
Securities held to maturity	3,790,000	3,776,000
Loans, net and loans held for sale	1,314,799,000	1,290,663,000
Accrued interest receivable	3,666,000	3,758,000
Financial liabilities:
Securities sold under agreements to repurchase	0	10,000,000
FHLBNY overnight advances	58,950,000	57,700,000
FHLBNY term advances	0	2,000,000
Recurring
Financial assets:
Available-for-sale Securities, Equity Securities	1,277,000	1,192,000
Securities available for sale	265,157,000	293,091,000
Derivative assets	2,304,000	974,000
Financial liabilities:
Derivative liabilities	2,322,000	1,049,000
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets:
Cash and due from financial institutions	30,837,000	27,966,000
Interest-earning deposits in other financial institutions	3,978,000	2,763,000
Available-for-sale Securities, Equity Securities	1,277,000	1,192,000
Securities available for sale	0	0
Securities held to maturity	0	0
FHLBNY and FRBNY stock	0	0
Loans, net and loans held for sale	0	0
Loans held for sale		0
Accrued interest receivable	1,000	1,000
Derivative assets	0	0
Financial liabilities:
Demand, savings, and insured money market accounts	1,332,815,000	1,349,084,000
Time deposits	0	0
Securities sold under agreements to repurchase		0
FHLBNY overnight advances	0	0
FHLBNY term advances		0
Accrued interest payable	21,000	24,000
Derivative liabilities	0	0
Recurring | Significant Other Observable Inputs (Level 2)
Financial assets:
Cash and due from financial institutions	0	0
Interest-earning deposits in other financial institutions	0	0
Available-for-sale Securities, Equity Securities	0	0
Securities available for sale	265,157,000	293,091,000
Securities held to maturity	2,309,000	1,830,000
FHLBNY and FRBNY stock	0	0
Loans, net and loans held for sale	0	0
Loans held for sale		542,000
Accrued interest receivable	737,000	867,000
Derivative assets	2,304,000	974,000
Financial liabilities:
Demand, savings, and insured money market accounts	0	0
Time deposits	146,315,000	118,598,000
Securities sold under agreements to repurchase		10,058,000
FHLBNY overnight advances	58,949,000	57,700,000
FHLBNY term advances		2,001,000
Accrued interest payable	94,000	124,000
Derivative liabilities	2,304,000	974,000
Recurring | Significant Unobservable Inputs (Level 3)
Financial assets:
Cash and due from financial institutions	0	0
Interest-earning deposits in other financial institutions	0	0
Available-for-sale Securities, Equity Securities	0	0
Securities available for sale	0	0
Securities held to maturity	1,481,000	1,946,000
FHLBNY and FRBNY stock	0	0
Loans, net and loans held for sale	1,296,697,000	1,289,584,000
Loans held for sale		0
Accrued interest receivable	3,666,000	3,774,000
Derivative assets	0	0
Financial liabilities:
Demand, savings, and insured money market accounts	0	0
Time deposits	0	0
Securities sold under agreements to repurchase		0
FHLBNY overnight advances	0	0
FHLBNY term advances		0
Accrued interest payable	0	0
Derivative liabilities	18,000	75,000
Recurring | Carrying Amount
Financial assets:
Cash and due from financial institutions	30,837,000	27,966,000
Interest-earning deposits in other financial institutions	3,978,000	2,763,000
Available-for-sale Securities, Equity Securities	1,277,000	1,192,000
Securities available for sale	265,157,000	293,091,000
Securities held to maturity	3,806,000	3,781,000
FHLBNY and FRBNY stock	5,816,000	5,784,000
Loans, net and loans held for sale	1,315,483,000	1,291,205,000
Loans held for sale		542,000
Accrued interest receivable	4,404,000	4,642,000
Derivative assets	2,304,000	974,000
Financial liabilities:
Demand, savings, and insured money market accounts	1,332,815,000	1,349,084,000
Time deposits	146,094,000	118,362,000
Securities sold under agreements to repurchase		10,000,000
FHLBNY overnight advances	58,950,000	57,700,000
FHLBNY term advances		2,000,000
Accrued interest payable	115,000	148,000
Derivative liabilities	2,322,000	1,049,000
Recurring | Estimated Fair Value
Financial assets:
Cash and due from financial institutions	30,837,000	27,966,000
Interest-earning deposits in other financial institutions	3,978,000	2,763,000
Available-for-sale Securities, Equity Securities	1,277,000	1,192,000
Securities available for sale	265,157,000	293,091,000
Securities held to maturity	3,790,000	3,776,000
Loans, net and loans held for sale	1,296,697,000	1,289,584,000
Loans held for sale		542,000
Accrued interest receivable	4,404,000	4,642,000
Derivative assets	2,304,000	974,000
Financial liabilities:
Demand, savings, and insured money market accounts	1,332,815,000	1,349,084,000
Time deposits	146,315,000	118,598,000
Securities sold under agreements to repurchase		10,058,000
FHLBNY overnight advances	58,949,000	57,700,000
FHLBNY term advances		2,001,000
Accrued interest payable	115,000	148,000
Derivative liabilities	$ 2,322,000	$ 1,049,000