SECURITIES AVAILABLE FOR SALE - Summary of Amortized Cost and Fair Value and Corresponding Amounts of Gross Unrealized Gains and Losses (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 490,993	$ 469,607
Gross Unrealized Gains	5,582	2,432
Gross Unrealized Losses	6,189	6,195
Fair Value	490,386	465,844
States and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	83,607	144,596
Gross Unrealized Gains	4,288	1,919
Gross Unrealized Losses	32	1,511
Fair Value	87,863	145,004
GSE residential CMOs
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	67,928	110,421
Gross Unrealized Gains	1,000	332
Gross Unrealized Losses	774	2,689
Fair Value	68,154	108,064
Non-agency CMOs
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	17,210
Gross Unrealized Gains	0
Gross Unrealized Losses	123
Fair Value	17,087
Private label residential CMOs
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		144
Gross Unrealized Gains		0
Gross Unrealized Losses		1
Fair Value		143
Private label commercial CMOs
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	86,704	75,911
Gross Unrealized Gains	156	55
Gross Unrealized Losses	231	921
Fair Value	86,629	75,045
Asset-backed and other
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	235,544	138,535
Gross Unrealized Gains	138	126
Gross Unrealized Losses	5,029	1,073
Fair Value	$ 230,653	$ 137,588

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).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Amount 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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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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