MARKETABLE SECURITIES - Schedule of Amortized Cost and Fair Value of Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Available for sale:
Amortized Cost	$ 242,415	$ 235,849
Gross Unrealized Gains	3	69
Gross Unrealized Losses	7,343	3,546
Estimated Fair Value	235,075	232,372
Held to maturity:
Amortized Cost	170,408	174,684
Gross Unrealized Gains	1,334	2,554
Gross Unrealized Losses	2,061	448
Estimated Fair Value	169,681	176,790
Corporate bonds
Available for sale:
Amortized Cost	18,803	18,823
Gross Unrealized Gains	0	64
Gross Unrealized Losses	558	50
Estimated Fair Value	18,245	18,837
Municipal securities
Available for sale:
Amortized Cost	7,722	7,746
Gross Unrealized Gains	0	0
Gross Unrealized Losses	257	200
Estimated Fair Value	7,465	7,546
Mortgage-backed securities
Available for sale:
Amortized Cost	97,654	92,471
Gross Unrealized Gains	0	0
Gross Unrealized Losses	3,490	1,793
Estimated Fair Value	94,164	90,678
Collateralized mortgage obligations
Available for sale:
Amortized Cost	118,236	116,809
Gross Unrealized Gains	3	5
Gross Unrealized Losses	3,038	1,503
Estimated Fair Value	115,201	115,311
Municipal securities
Held to maturity:
Amortized Cost	143,772	146,496
Gross Unrealized Gains	1,107	2,244
Gross Unrealized Losses	1,557	218
Estimated Fair Value	143,322	148,522
Mortgage-backed securities
Held to maturity:
Amortized Cost	20,919	22,026
Gross Unrealized Gains	143	199
Gross Unrealized Losses	478	230
Estimated Fair Value	20,584	21,995
Collateralized mortgage obligations
Held to maturity:
Amortized Cost	5,717	6,162
Gross Unrealized Gains	84	111
Gross Unrealized Losses	26	0
Estimated Fair Value	$ 5,775	$ 6,273

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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