FAIR VALUES OF FINANCIAL INSTRUMENTS: (Details 2) $ in Thousands	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
State and municipal obligations | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	$ 1,895	$ 2,565
Other Real Estate | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	1,012	3,625
Impaired Loans | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	$ 6,581	$ 100
Measurement Input, Default Rate [Member] | State And Municipal Obligations
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	0	0
Measurement Input, Discount Rate [Member] | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	0
Measurement Input, Discount Rate [Member] | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	0.50
Measurement Input, Discount Rate [Member] | State and municipal obligations | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	0.0341	0.0287
Measurement Input, Discount Rate [Member] | State and municipal obligations | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	0.0444	0.0444
Measurement Input, Discount Rate [Member] | Other Real Estate | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	0.0500	0.0500
Measurement Input, Discount Rate [Member] | Other Real Estate | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	0.2000	0.2000
Measurement Input, Discount Rate [Member] | Impaired Loans | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	0.0000	0.0000
Measurement Input, Discount Rate [Member] | Impaired Loans | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	0.5000	0.5000