MARKETABLE SECURITIES - Schedule of Amortized Cost and Fair Value of Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Available for sale:
Amortized Cost	$ 251,428	$ 235,849
Gross Unrealized Gains	48	69
Gross Unrealized Losses	7,986	3,546
Estimated Fair Value	243,490	232,372
Held to maturity:
Amortized Cost	167,239	174,684
Gross Unrealized Gains	1,190	2,554
Gross Unrealized Losses	1,988	448
Estimated Fair Value	166,441	176,790
Corporate bonds
Available for sale:
Amortized Cost	18,784	18,823
Gross Unrealized Gains	0	64
Gross Unrealized Losses	643	50
Estimated Fair Value	18,141	18,837
Municipal securities
Available for sale:
Amortized Cost	18,211	7,746
Gross Unrealized Gains	48	0
Gross Unrealized Losses	305	200
Estimated Fair Value	17,954	7,546
Mortgage-backed securities
Available for sale:
Amortized Cost	95,062	92,471
Gross Unrealized Gains	0	0
Gross Unrealized Losses	3,820	1,793
Estimated Fair Value	91,242	90,678
Collateralized mortgage obligations
Available for sale:
Amortized Cost	119,371	116,809
Gross Unrealized Gains	0	5
Gross Unrealized Losses	3,218	1,503
Estimated Fair Value	116,153	115,311
Municipal securities
Held to maturity:
Amortized Cost	143,295	146,496
Gross Unrealized Gains	1,041	2,244
Gross Unrealized Losses	1,481	218
Estimated Fair Value	142,855	148,522
Mortgage-backed securities
Held to maturity:
Amortized Cost	18,880	22,026
Gross Unrealized Gains	88	199
Gross Unrealized Losses	472	230
Estimated Fair Value	18,496	21,995
Collateralized mortgage obligations
Held to maturity:
Amortized Cost	5,064	6,162
Gross Unrealized Gains	61	111
Gross Unrealized Losses	35	0
Estimated Fair Value	$ 5,090	$ 6,273

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

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Amount of debt securities categorized neither as held-to-maturity nor trading.

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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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