FAIR VALUE (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets measured at fair value on recurring basis
Available for sale securities	$ 792,058	$ 819,722
U.S. GSE securities
Assets measured at fair value on recurring basis
Available for sale securities	64,228	63,649
State and municipal obligations
Assets measured at fair value on recurring basis
Available for sale securities	91,320	116,165
U.S. GSE residential mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities	193,404	158,048
U.S. GSE residential collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities	319,202	367,511
U.S. GSE commercial mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities	6,153	6,307
U.S. GSE commercial collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities	50,386	55,192
Other asset backed securities
Assets measured at fair value on recurring basis
Available for sale securities	23,037	22,553
Corporate bonds
Assets measured at fair value on recurring basis
Available for sale securities	44,328	30,297
Carrying Value
Assets measured at fair value on recurring basis
Available for sale securities	792,058	819,722
Financial Assets: Derivatives	2,447	2,510
Financial Liabilities:
Financial liabilities: Derivatives	1,719	1,670
Fair Value
Assets measured at fair value on recurring basis
Available for sale securities	792,058	819,722
Financial Assets: Derivatives	2,447	2,510
Financial Liabilities:
Financial liabilities: Derivatives	1,719	1,670
Significant Other Observable Inputs (Level 2) | Fair Value
Assets measured at fair value on recurring basis
Available for sale securities	792,058	819,722
Financial Assets: Derivatives	2,447	2,510
Financial Liabilities:
Financial liabilities: Derivatives	1,719	1,670
Recurring basis | Carrying Value
Assets measured at fair value on recurring basis
Available for sale securities	792,058	819,722
Recurring basis | Carrying Value | U.S. GSE securities
Assets measured at fair value on recurring basis
Available for sale securities	64,228	63,649
Recurring basis | Carrying Value | State and municipal obligations
Assets measured at fair value on recurring basis
Available for sale securities	91,320	116,165
Recurring basis | Carrying Value | U.S. GSE residential mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities	193,404	158,048
Recurring basis | Carrying Value | U.S. GSE residential collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities	319,202	367,511
Recurring basis | Carrying Value | U.S. GSE commercial mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities	6,153	6,307
Recurring basis | Carrying Value | U.S. GSE commercial collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities	50,386	55,192
Recurring basis | Carrying Value | Other asset backed securities
Assets measured at fair value on recurring basis
Available for sale securities	23,037	22,553
Recurring basis | Carrying Value | Corporate bonds
Assets measured at fair value on recurring basis
Available for sale securities	44,328	30,297
Recurring basis | Carrying Value | Derivatives
Assets measured at fair value on recurring basis
Financial Assets: Derivatives	2,447	2,510
Financial Liabilities:
Financial liabilities: Derivatives	1,719	1,670
Recurring basis | Significant Other Observable Inputs (Level 2) | Fair Value
Assets measured at fair value on recurring basis
Available for sale securities	792,058	819,722
Recurring basis | Significant Other Observable Inputs (Level 2) | Fair Value | U.S. GSE securities
Assets measured at fair value on recurring basis
Available for sale securities	64,228	63,649
Recurring basis | Significant Other Observable Inputs (Level 2) | Fair Value | State and municipal obligations
Assets measured at fair value on recurring basis
Available for sale securities	91,320	116,165
Recurring basis | Significant Other Observable Inputs (Level 2) | Fair Value | U.S. GSE residential mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities	193,404	158,048
Recurring basis | Significant Other Observable Inputs (Level 2) | Fair Value | U.S. GSE residential collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities	319,202	367,511
Recurring basis | Significant Other Observable Inputs (Level 2) | Fair Value | U.S. GSE commercial mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities	6,153	6,307
Recurring basis | Significant Other Observable Inputs (Level 2) | Fair Value | U.S. GSE commercial collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities	50,386	55,192
Recurring basis | Significant Other Observable Inputs (Level 2) | Fair Value | Other asset backed securities
Assets measured at fair value on recurring basis
Available for sale securities	23,037	22,553
Recurring basis | Significant Other Observable Inputs (Level 2) | Fair Value | Corporate bonds
Assets measured at fair value on recurring basis
Available for sale securities	44,328	30,297
Recurring basis | Significant Other Observable Inputs (Level 2) | Fair Value | Derivatives
Assets measured at fair value on recurring basis
Financial Assets: Derivatives	2,447	2,510
Financial Liabilities:
Financial liabilities: Derivatives	$ 1,719	$ 1,670