SHARE-BASED COMPENSATION PLANS - Summary of Restricted Shares Compensation Expense (Details) - Orrstown 2011 Incentive Stock Plan - Restricted Stock - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted share award expense	$ 1,323	$ 5,577	$ 3,964	$ 7,386
Restricted share award tax benefit	278	1,171	832	1,551
Fair value of shares vested	$ 4,273	$ 286	$ 5,778	$ 9,658