ORRSTOWN FINANCIAL SERVICES, INC. (PARENT COMPANY ONLY) CONDENSED FINANCIAL INFORMATION - Condensed Statements of Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income
Other income	$ 331	$ 320	$ 190
Expenses
Interest on short-term borrowings	623	1,577	784
Interest on subordinated notes	1,987	73	0
Total interest expense	23,699	13,511	7,644
Share-based compensation	1,586	1,493	1,386
Merger related and branch consolidation expenses	8,964	3,197	0
Income tax benefit	2,710	1,640	4,338
Net income	16,924	12,805	8,090
Consolidated
Income
Dividends from subsidiaries	2,000	4,450	0
Interest income subsidiary from bank subsidiary	257	7	15
Other income	55	102	61
Total income	2,312	4,559	76
Expenses
Interest on short-term borrowings	0	57	0
Interest on subordinated notes	1,987	73	0
Total interest expense	1,987	130	0
Share-based compensation	236	205	247
Management fee to bank subsidiary	1,350	1,042	501
Merger related and branch consolidation expenses	1,574	1,545	0
Other expenses	802	656	1,116
Total expenses	5,949	3,578	1,864
Income (loss) before income tax benefit and equity in undistributed income of subsidiaries	(3,637)	981	(1,788)
Income tax benefit	(1,182)	(735)	(596)
Income (loss) before equity in undistributed income of subsidiaries	(2,455)	1,716	(1,192)
Equity in undistributed income of subsidiaries	19,379	11,089	9,282
Net income	$ 16,924	$ 12,805	$ 8,090