ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Reclassification Adjustments Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Unrealized gains/(losses) on investments available-for-sale Affected line item in the Statements of Income:
Investment securities gains	$ 58	$ 169
Income before taxes	58	169
Tax expense	(15)	(42)
Net income	43	127
Amortization of defined benefit pension plan items Affected line item in the Statements of Income:
Recognized actuarial loss	(227)	(219)
Loss before taxes	(227)	(219)
Tax benefit	63	55
Net loss	$ (164)	$ (164)

Amount, before tax and adjustment, of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.

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Amount, before tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount before tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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Amount after tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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Amount, before tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

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