INVESTMENT SECURITIES - Amortized Cost and Fair Values of AFS Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 497,454	$ 491,492
Gross Unrealized Gains	8,263	5,582
Gross Unrealized Losses	26,118	6,189
Fair Value	479,599	490,885
States and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	105,572	83,607
Gross Unrealized Gains	6,111	4,288
Gross Unrealized Losses	626	32
Fair Value	111,057	87,863
GSE residential MBSs
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,551
Gross Unrealized Gains	55
Gross Unrealized Losses	0
Fair Value	4,606
GSE residential CMOs
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	66,134	67,928
Gross Unrealized Gains	2,022	1,000
Gross Unrealized Losses	941	774
Fair Value	67,215	68,154
Non-agency CMOs
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	17,161	17,210
Gross Unrealized Gains	0	0
Gross Unrealized Losses	482	123
Fair Value	16,679	17,087
Private label commercial CMOs
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	73,978	86,704
Gross Unrealized Gains	0	156
Gross Unrealized Losses	7,844	231
Fair Value	66,134	86,629
Asset-backed
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	229,461	235,406
Gross Unrealized Gains	75	138
Gross Unrealized Losses	16,225	5,029
Fair Value	213,311	230,515
Other
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	597	637
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 597	$ 637

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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