FAIR VALUE OF FINANCIAL ASSETS AND LIABILITIES (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	$ 1,166,319	$ 1,126,983
Equity securities, at fair value	1,204	1,127
States and political subdivisions
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	168,589	122,018
Corporate securities
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	50,558	30,529
U.S. Treasury obligations and direct obligations of U.S Government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	34,944	40,381
Mortgage Backed Securities Residential U S Government Sponsored Entities [Member]
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	763,326	677,822
Commercial - U.S. Government agencies and sponsored entities
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	73,786	81,225
Residential - Non-government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	28,676	37,191
Commercial - Non-government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	46,440	137,817
Equity securities
Assets and liabilities measured at fair value
Equity securities, at fair value	1,204	1,127
Recurring basis
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	1,166,319	1,126,983
Total	1,167,507	1,128,090
Recurring basis | Derivative - Interest Rate Contracts
Assets and liabilities measured at fair value
Derivatives: Interest rate lock and forward sale commitments	(16)	(20)
Recurring basis | States and political subdivisions
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	168,589	122,018
Recurring basis | Corporate securities
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	50,558	30,529
Recurring basis | U.S. Treasury obligations and direct obligations of U.S Government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	34,944	40,381
Recurring basis | Mortgage Backed Securities Residential U S Government Sponsored Entities [Member]
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	763,326	677,822
Recurring basis | Commercial - U.S. Government agencies and sponsored entities
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	73,786	81,225
Recurring basis | Residential - Non-government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	28,676	37,191
Recurring basis | Commercial - Non-government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	46,440	137,817
Recurring basis | Equity securities
Assets and liabilities measured at fair value
Equity securities, at fair value	1,204	1,127
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Total	1,204	1,127
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivative - Interest Rate Contracts
Assets and liabilities measured at fair value
Derivatives: Interest rate lock and forward sale commitments	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | States and political subdivisions
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate securities
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury obligations and direct obligations of U.S Government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mortgage Backed Securities Residential U S Government Sponsored Entities [Member]
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial - U.S. Government agencies and sponsored entities
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential - Non-government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial - Non-government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity securities
Assets and liabilities measured at fair value
Equity securities, at fair value	1,204	1,127
Recurring basis | Significant Other Observable Inputs (Level 2)
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	1,153,791	1,115,728
Total	1,153,829	1,115,708
Recurring basis | Significant Other Observable Inputs (Level 2) | Derivative - Interest Rate Contracts
Assets and liabilities measured at fair value
Derivatives: Interest rate lock and forward sale commitments	38	(20)
Recurring basis | Significant Other Observable Inputs (Level 2) | States and political subdivisions
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	157,055	110,763
Recurring basis | Significant Other Observable Inputs (Level 2) | Corporate securities
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	50,558	30,529
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. Treasury obligations and direct obligations of U.S Government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	34,944	40,381
Recurring basis | Significant Other Observable Inputs (Level 2) | Mortgage Backed Securities Residential U S Government Sponsored Entities [Member]
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	763,326	677,822
Recurring basis | Significant Other Observable Inputs (Level 2) | Commercial - U.S. Government agencies and sponsored entities
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	73,786	81,225
Recurring basis | Significant Other Observable Inputs (Level 2) | Residential - Non-government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	27,682	37,191
Recurring basis | Significant Other Observable Inputs (Level 2) | Commercial - Non-government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	46,440	137,817
Recurring basis | Significant Other Observable Inputs (Level 2) | Equity securities
Assets and liabilities measured at fair value
Equity securities, at fair value	0	0
Recurring basis | Significant Unobservable Inputs (Level 3)
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	12,528	11,255
Total	12,474	11,255
Recurring basis | Significant Unobservable Inputs (Level 3) | Derivative - Interest Rate Contracts
Assets and liabilities measured at fair value
Derivatives: Interest rate lock and forward sale commitments	(54)	0
Recurring basis | Significant Unobservable Inputs (Level 3) | States and political subdivisions
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	11,534	11,255
Recurring basis | Significant Unobservable Inputs (Level 3) | Corporate securities
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Recurring basis | Significant Unobservable Inputs (Level 3) | U.S. Treasury obligations and direct obligations of U.S Government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Recurring basis | Significant Unobservable Inputs (Level 3) | Mortgage Backed Securities Residential U S Government Sponsored Entities [Member]
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Recurring basis | Significant Unobservable Inputs (Level 3) | Commercial - U.S. Government agencies and sponsored entities
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Recurring basis | Significant Unobservable Inputs (Level 3) | Residential - Non-government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	994	0
Recurring basis | Significant Unobservable Inputs (Level 3) | Commercial - Non-government agencies
Assets and liabilities measured at fair value
Available-for-sale debt securities, at fair value	0	0
Recurring basis | Significant Unobservable Inputs (Level 3) | Equity securities
Assets and liabilities measured at fair value
Equity securities, at fair value	$ 0	$ 0