SECURITIES (Schedule of Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Securities [Line Items]
Securities—trading, Amortized Cost	$ 27,340	$ 27,246
Securities—trading	25,764	22,318
Available-for-sale Securities, Amortized Cost	1,451,897	926,112
Available-for-sale Securities, Gross Unrealized Gains	280	1,936
Available-for-sale Securities, Gross Unrealized Losses	(39,904)	(8,563)
Securities—available-for-sale	1,412,273	919,485
Held-to-maturity Securities, Amortized Cost	258,699	260,271
Held-to-maturity Securities, Gross Unrealized Gains	1,451	3,687
Held-to-maturity Securities, Gross Unrealized Losses	6,056	1,770
Securities—held-to-maturity	254,094	262,188
U.S. Government and agency obligations [Member]
Schedule of Securities [Line Items]
Available-for-sale Securities, Amortized Cost	139,329	72,829
Available-for-sale Securities, Gross Unrealized Gains	9	68
Available-for-sale Securities, Gross Unrealized Losses	(3,030)	(431)
Securities—available-for-sale	136,308	72,466
Held-to-maturity Securities, Amortized Cost	1,007	1,024
Held-to-maturity Securities, Gross Unrealized Gains	18	29
Held-to-maturity Securities, Gross Unrealized Losses	4	0
Securities—held-to-maturity	1,021	1,053
Municipal bonds [Member]
Schedule of Securities [Line Items]
Securities—trading, Amortized Cost	100	100
Securities—trading	100	100
Available-for-sale Securities, Amortized Cost	66,854	68,513
Available-for-sale Securities, Gross Unrealized Gains	152	665
Available-for-sale Securities, Gross Unrealized Losses	(1,020)	(445)
Securities—available-for-sale	65,986	68,733
Held-to-maturity Securities, Amortized Cost	191,777	189,860
Held-to-maturity Securities, Gross Unrealized Gains	1,433	3,385
Held-to-maturity Securities, Gross Unrealized Losses	3,773	1,252
Securities—held-to-maturity	189,437	191,993
Corporate bonds [Member]
Schedule of Securities [Line Items]
Securities—trading, Amortized Cost	27,240	27,132
Securities—trading	25,664	22,058
Available-for-sale Securities, Amortized Cost	5,054	5,431
Available-for-sale Securities, Gross Unrealized Gains	4	6
Available-for-sale Securities, Gross Unrealized Losses	(18)	(44)
Securities—available-for-sale	5,040	5,393
Held-to-maturity Securities, Amortized Cost	3,771	3,978
Held-to-maturity Securities, Gross Unrealized Gains	0	7
Held-to-maturity Securities, Gross Unrealized Losses	20	0
Securities—held-to-maturity	3,751	3,985
Mortgage-backed or related securities [Member]
Schedule of Securities [Line Items]
Available-for-sale Securities, Amortized Cost	1,218,204	745,956
Available-for-sale Securities, Gross Unrealized Gains	29	1,003
Available-for-sale Securities, Gross Unrealized Losses	(35,715)	(7,402)
Securities—available-for-sale	1,182,518	739,557
Held-to-maturity Securities, Amortized Cost	62,144	65,409
Held-to-maturity Securities, Gross Unrealized Gains	0	266
Held-to-maturity Securities, Gross Unrealized Losses	2,259	518
Securities—held-to-maturity	59,885	65,157
Asset-backed Securities [Member]
Schedule of Securities [Line Items]
Available-for-sale Securities, Amortized Cost	22,456	27,667
Available-for-sale Securities, Gross Unrealized Gains	86	184
Available-for-sale Securities, Gross Unrealized Losses	(121)	(93)
Securities—available-for-sale	$ 22,421	27,758
Equity Securities [Member]
Schedule of Securities [Line Items]
Securities—trading, Amortized Cost		14
Securities—trading		160
Available-for-sale Securities, Amortized Cost		5,716
Available-for-sale Securities, Gross Unrealized Gains		10
Available-for-sale Securities, Gross Unrealized Losses		(148)
Securities—available-for-sale		$ 5,578

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 gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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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 of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

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Amount, before other-than-temporary impairment (OTTI) accretion, of investment in debt securities measured at amortized cost (held-to-maturity).

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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