ESTIMATED FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Assets measured at fair value on recurring basis
Available for sale securities	$ 883,626	$ 800,203
U.S. GSE securities
Assets measured at fair value on recurring basis
Available for sale securities	67,306	62,674
State and municipal obligations
Assets measured at fair value on recurring basis
Available for sale securities	103,679	87,935
U.S. GSE residential mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities	216,524	200,264
U.S. GSE residential collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities	360,863	317,878
U.S. GSE commercial mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities	12,656	12,418
U.S. GSE commercial collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities	69,061	64,198
Other asset backed securities
Assets measured at fair value on recurring basis
Available for sale securities	22,310	22,371
Corporate bonds
Assets measured at fair value on recurring basis
Available for sale securities	$ 31,227	$ 32,465
Quoted Prices In Active Markets for Identical Assets (Level 1)
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Significant Other Observable Inputs (Level 2)
Assets measured at fair value on recurring basis
Available for sale securities	$ 883,626	$ 800,203
Significant Unobservable Inputs (Level 3)
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Carrying Value
Assets measured at fair value on recurring basis
Available for sale securities	$ 883,626	$ 800,203
Recurring basis | Quoted Prices In Active Markets for Identical Assets (Level 1)
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Quoted Prices In Active Markets for Identical Assets (Level 1) | U.S. GSE securities
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Quoted Prices In Active Markets for Identical Assets (Level 1) | State and municipal obligations
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Quoted Prices In Active Markets for Identical Assets (Level 1) | U.S. GSE residential mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Quoted Prices In Active Markets for Identical Assets (Level 1) | U.S. GSE residential collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Quoted Prices In Active Markets for Identical Assets (Level 1) | U.S. GSE commercial mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Quoted Prices In Active Markets for Identical Assets (Level 1) | U.S. GSE commercial collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Quoted Prices In Active Markets for Identical Assets (Level 1) | Other asset backed securities
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Quoted Prices In Active Markets for Identical Assets (Level 1) | Corporate bonds
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Quoted Prices In Active Markets for Identical Assets (Level 1) | Derivatives
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Significant Other Observable Inputs (Level 2)
Assets measured at fair value on recurring basis
Available for sale securities	$ 883,626	$ 800,203
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. GSE securities
Assets measured at fair value on recurring basis
Available for sale securities	67,306	62,674
Recurring basis | Significant Other Observable Inputs (Level 2) | State and municipal obligations
Assets measured at fair value on recurring basis
Available for sale securities	103,679	87,935
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. GSE residential mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities	216,524	200,264
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. GSE residential collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities	360,863	317,878
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. GSE commercial mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities	12,656	12,418
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. GSE commercial collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities	69,061	64,198
Recurring basis | Significant Other Observable Inputs (Level 2) | Other asset backed securities
Assets measured at fair value on recurring basis
Available for sale securities	22,310	22,371
Recurring basis | Significant Other Observable Inputs (Level 2) | Corporate bonds
Assets measured at fair value on recurring basis
Available for sale securities	31,227	32,465
Recurring basis | Significant Other Observable Inputs (Level 2) | Derivatives
Assets measured at fair value on recurring basis
Available for sale securities	2,096	779
Financial Liabilities:
Derivatives	$ 5,162	$ 2,073
Recurring basis | Significant Unobservable Inputs (Level 3)
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Significant Unobservable Inputs (Level 3) | U.S. GSE securities
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Significant Unobservable Inputs (Level 3) | State and municipal obligations
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Significant Unobservable Inputs (Level 3) | U.S. GSE residential mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Significant Unobservable Inputs (Level 3) | U.S. GSE residential collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Significant Unobservable Inputs (Level 3) | U.S. GSE commercial mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Significant Unobservable Inputs (Level 3) | U.S. GSE commercial collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Significant Unobservable Inputs (Level 3) | Other asset backed securities
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Significant Unobservable Inputs (Level 3) | Corporate bonds
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Significant Unobservable Inputs (Level 3) | Derivatives
Assets measured at fair value on recurring basis
Available for sale securities
Financial Liabilities:
Derivatives
Recurring basis | Carrying Value
Assets measured at fair value on recurring basis
Available for sale securities	$ 883,626	$ 800,203
Recurring basis | Carrying Value | U.S. GSE securities
Assets measured at fair value on recurring basis
Available for sale securities	67,306	62,674
Recurring basis | Carrying Value | State and municipal obligations
Assets measured at fair value on recurring basis
Available for sale securities	103,679	87,935
Recurring basis | Carrying Value | U.S. GSE residential mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities	216,524	200,264
Recurring basis | Carrying Value | U.S. GSE residential collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities	360,863	317,878
Recurring basis | Carrying Value | U.S. GSE commercial mortgage-backed securities
Assets measured at fair value on recurring basis
Available for sale securities	12,656	12,418
Recurring basis | Carrying Value | U.S. GSE commercial collateralized mortgage obligations
Assets measured at fair value on recurring basis
Available for sale securities	69,061	64,198
Recurring basis | Carrying Value | Other asset backed securities
Assets measured at fair value on recurring basis
Available for sale securities	22,310	22,371
Recurring basis | Carrying Value | Corporate bonds
Assets measured at fair value on recurring basis
Available for sale securities	31,227	32,465
Recurring basis | Carrying Value | Derivatives
Assets measured at fair value on recurring basis
Available for sale securities	2,096	779
Financial Liabilities:
Derivatives	$ 5,162	$ 2,073