SHARE-BASED COMPENSATION PLANS - Summary of Restricted Shares Compensation Expense (Details) - Orrstown 2011 Incentive Stock Plan - Restricted Stock - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted share award expense	$ 1,533	$ 1,354
Restricted share award tax benefit	322	284
Fair value of shares vested	$ 2,653	$ 1,475